Topics and questions for coding challenges

Big O

https://www.bigocheatsheet.com/

Big O Basic Concepts

O(1): Constant Time

1. Doesn’t depend on the size of the data set.
2. Example: Accessing an array element by its index.

O(log n): Logarithmic Time

1. Splits the data in each step (divide and conquer).
2. Example: Binary search.

O(n): Linear Time

1. Directly proportional to the data set size.
2. Example: Looping through an array.

O(n log n): Linearithmic Time

1. Splits and sorts or searches data.
2. Example: Merge sort, quick sort.

O(n2): Polynomial Time

1. Nested loops for each power of n.
2. Example: Bubble sort (O(n2)).

Omega (Ω) – Best Case

1. What it means: Omega (Ω) describes the best-case scenario for an algorithm.
2. In simple terms: It tells you the fastest an algorithm can run in the best circumstances.

Theta (Θ) - Average Case

1. In simple terms: It tells you what to generally expect in terms of time complexity.

Big O (O) - Worst Case

1. What it means: Big O (O) describes the worst-case scenario for an algorithm.
2. In simple terms: It tells you the slowest an algorithm can run in the worst circumstances.

Drop Constants

1. O(2n) simplifies to O(n).

Drop Non-Dominant Terms

1. In O(n^2 + n), focus on O(n^2) as it will dominate for large n.

Algorithms and Data Structures

1. Data Structures
2. Data types
3. Trees
4. Searching algorithms
5. Sorting algorithms
6. Bitwise operations
7. Greatest Common Divisor (GCD)
8. Least Common Multiple (LCM)
9. Logarithms and Exponentials
10. Divide, Conquer and Combine paradigm
11. Permutations

System design

1. design a distributed datastore for a movie recommendation site.
   1. Could you design an analytics tracking system to monitor all of the orders going through the site? How about building a flow so users can upload videos?
2. How does Twitter or Facebook Messenger work? What are the underlying technologies?

The coolest part is that many companies share details of how they designed parts of their systems. Uber, for example, has tons of great articles on their engineering blog (LINK) about how they built out different pieces of technology.

This first step is very much a research process. Google “facebook messenger technology” or check out sites like Gainlo where he breaks down these sorts of design problems.

Object Oriented design questions

1. What classes they would define.
2. What methods go in each class (including signatures).
3. What the class constructors are responsible for.
4. What data structures the class will have to maintain.
5. Whether any Design Patterns are applicable to this problem.

Design a deck of cards that can be used for different card game applications.

Likely classes: a Deck, a Card, a Hand, a Board, and possibly Rank and Suit. Drill down on who’s responsible for creating new Decks, where they get shuffled, how you deal cards, etc. Do you need a different instance for every card in a casino in Vegas?

Model the Animal kingdom as a class system, for use in a Virtual Zoo program.

Possible sub-issues: do they know the animal kingdom at all? (I.e. common sense.) What properties and methods do they immediately think are the most important? Do they use abstract classes and/or interfaces to represent shared stuff? How do they handle the multiple-inheritance problem posed by, say, a tomato (fruit or veggie?), a sponge (animal or plant?), or a mule (donkey or horse?)

Create a class design to represent a filesystem.

Do they even know what a filesystem is, and what services it provides? Likely classes: Filesystem, Directory, File, Permission. What’s their relationship? How do you differentiate between text and binary files, or do you need to? What about executable files? How do they model a Directory containing many files? Do they use a data structure for it? Which one, and what performance tradeoffs does it have?

Design an OO representation to model HTML.

How do they represent tags and content? What about containment relationships? Bonus points if they know that this has already been done a bunch of times, e.g. with DOM. But they still have to describe it.

The following commonly-asked OO design interview questions are probably too involved to be good phone-screen weeders:

Design a parking garage.

Design a bank of elevators in a skyscraper.

Model the monorail system at Disney World.

Design a restaurant-reservation system.

Design a hotel room-reservation system. See https://github.com/zeevolution/hotel-reservation

Research the following topics (read on wikipedia):

1. Birthday problem
2. Self-organizing list
3. Self-balancing binary search tree
4. Locality of reference
5. CPU Cache
6. Dynamic perfect hashing
7. Fusion tree
8. Cunningham’s law
9. MonteCarlo simulation
10. The Hungarian algorithm
11. Luhn algorithm - https://www.geeksforgeeks.org/luhn-algorithm/
12. staircase problem - make it generic. any combination of steps that can be taken to get to the top.
13. The traveling salesman problem

Top 10 algorithms or algorithmic concepts for coding interviews - by Techlead and algoexpert

1. depth first search -

graph traversal or tree traversal

tree structures - getting to the leaf nodes and backtracking.

e.g. binary tree structure with letters in a string

2. breadth first search -

e.g. take a tree and print it level by level

difference between 1 and 2 it the order of traversal.

3. matching brackets problems

is it valid?

what is the next bracket to be added?

using stacks

other ways are possible but not very straightforward

4. making use of hashtables

e.g. 2D matrix - visit the matrix but somehow keep track of the elements that are already visited.

e.g. largest amount of zeroes that are next to each other.

use hashtable to make sure yu don’t revisit grid coordinates that are already visited.

e.g. nth fibonacci number

5. how to manipulate multiple variables or pointers at once:

e.g. using two pointers for a string

e.g. using two pointers to traverse a linked list and each of them are going at different speeds from one another.

e.g. longest palindromic substring in a string. for every letter, start two pointers going in the opposite directions.

6. reversing a linked list

e.g. are there duplicates in a linked list

e.g. remove the duplicates in a linked list

creating a class for the node and then using it for traversals

7. sorting fundamentals

quick sort, merge sort, insertion sort, heap sort, bubble sort

not to memorize them but understand them fundamentally.

know the runtimes for these sorts.

8. recursion

9. knowing how to construct custom datastructures.

e.g. suffix tree like datastructure.

capture a bunch of strings in a datastructure.

10. binary search

quick sort works similar to binary search.

What is a list of data structures that a competitive programmer must know?

Reference: https://qr.ae/pNLa3S

Sameer Gulati · Updated August 12, 2019 Competitive Programming · International Master at Codeforces

This is a comprehensive list of Data Structures and Algorithms used in Competitive Programming with tutorials, implementations and problems. Use this list in conjunction with this strategy (Sameer Gulati’s answer to What made you good at competitive programming?). I originally posted this list on the Codechef Discuss Forum. Moving forward I will be keeping this list updated here on Quora:

Binary Search

1. Tutorial, Problems - https://www.topcoder.com/community/data-science/data-science-tutorials/binary-search/
2. Tutorial, Implementation - https://geeksquiz.com/binary-search/
3. Problem -https://www.spoj.com/problems/AGGRCOW/

Quicksort

1. Tutorial, Implementation - http://geeksquiz.com/quick-sort/
2. Tutorial - https://www.topcoder.com/community/competitive-programming/tutorials/sorting

Merge Sort

1. Tutorial, Implementation - http://geeksquiz.com/merge-sort/
2. Tutorial - https://www.topcoder.com/community/competitive-programming/tutorials/sorting

Suffix Array

1. Tutorial - http://web.stanford.edu/class/cs97si/suffix-array.pdf
2. Tutorial, Implementation - http://discuss.codechef.com/questions/21385/a-tutorial-on-suffix-arrays
3. Tutorial, Implementation - http://apps.topcoder.com/forums/%3Bjsessionid%3DBC99925E58CB2628CA9AA3AFC13F6593?module=Thread&threadID=627379&start=0
4. Problem - http://www.spoj.com/problems/SUBST1/
5. Problem - http://www.codechef.com/problems/MOU1H

Knuth-Morris-Pratt Algorithm (KMP)

1. Tutorial - https://www.topcoder.com/community/data-science/data-science-tutorials/introduction-to-string-searching-algorithms/
2. Tutorial, Implementation - http://www.geeksforgeeks.org/searching-for-patterns-set-2-kmp-algorithm/
3. Tutorial - http://keithschwarz.com/interesting/code/?dir=knuth-morris-pratt
4. Problem - http://www.codechef.com/problems/TASHIFT

Rabin-Karp Algorithm

1. Tutorial, Implementation - http://www.geeksforgeeks.org/searching-for-patterns-set-3-rabin-karp-algorithm/
2. Tutorial - https://www.topcoder.com/community/competitive-programming/tutorials/introduction-to-string-searching-algorithms/
3. Problem - http://www.codechef.com/problems/SSTORY
4. Problem - http://codeforces.com/problemset/problem/271/D

Tries

1. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/using-tries/
2. Tutorial :
   1. I, - http://www.geeksforgeeks.org/trie-insert-and-search/
   2. II - http://www.geeksforgeeks.org/trie-delete/
3. Tutorial - https://www.quora.com/q/threadsiiithyderabad/Tutorial-on-Trie-and-example-problems
4. Problem -http://www.spoj.com/problems/SUBXOR/
5. Problem - https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&category=345&page=show_problem&problem=2683
6. Problem - http://www.codechef.com/problems/EST

Depth First Traversal of a Graph

1. Tutorial, Implementation - http://www.geeksforgeeks.org/depth-first-traversal-for-a-graph/
2. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/introduction-to-graphs-and-their-data-structures-section-2/
3. Problem - http://www.spoj.com/problems/PARADOX/
4. Problem - http://www.spoj.com/problems/BUGLIFE/
5. Problem -http://www.spoj.com/problems/PT07Z/

Breadth First Traversal of a Graph

1. Tutorial, Implementation - http://www.geeksforgeeks.org/breadth-first-traversal-for-a-graph/
2. Tutorial Problems - https://www.topcoder.com/community/competitive-programming/tutorials/introduction-to-graphs-and-their-data-structures-section-2/
3. Problem - http://www.codechef.com/problems/DIGJUMP
4. Problem - http://www.spoj.com/problems/ONEZERO/
5. Problem - http://www.spoj.com/problems/NAKANJ/
6. Flood Fill - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=findSolution#floodfill

Dijkstra’s Algorithm

1. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/introduction-to-graphs-and-their-data-structures-section-3/
2. Problem - http://www.codechef.com/problems/REN2013G
3. Tutorial(greedy) - http://e-maxx.ru/algo/dijkstra
4. Tutorial (with heap) - https://e-maxx.ru/algo/dijkstra_sparse
5. Implementation - http://zobayer.blogspot.in/2009/12/dijkstras-algorithm-in-c.html
6. Problem - http://www.spoj.com/problems/EZDIJKST/
7. Problem - http://www.spoj.com/problems/SHPATH/

Binary Indexed Tree

1. Tutorial, Problems - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=binaryIndexedTrees
2. Tutorial - http://codeforces.com/blog/entry/619
3. Original Paper - http://citeseerx.ist.psu.edu/viewdoc/download%3Bjsessionid%3DAB3AEBC0736E52FA815A3D4C633DE52F?doi=10.1.1.14.8917&rep=rep1&type=pdf
4. Tutorial - http://sanugupta.wordpress.com/2014/08/29/binary-indexed-tree-fenwick-tree/
5. Tutorial - http://cs.stackexchange.com/a/10541
6. Problem - http://www.spoj.com/problems/HORRIBLE/
7. Problem - http://www.spoj.com/problems/YODANESS/
8. Problem - http://www.spoj.com/problems/INVCNT/
9. Problem -http://www.spoj.com/problems/NICEDAY/
10. Problem - http://www.spoj.com/problems/CTRICK/
11. Problem - http://www.spoj.com/problems/DQUERY/
12. Problem - http://www.spoj.com/problems/MCHAOS/

Segment Tree (with lazy propagation)

1. Tutorial, Implementation - http://se7so.blogspot.in/2012/12/segment-trees-and-lazy-propagation.html
2. Tutorial - http://se7so.blogspot.in/2012/12/segment-trees-and-lazy-propagation.html
3. Tutorial, Problems, Implementation - http://letuskode.blogspot.in/2013/01/segtrees.html
4. Tutorial, Implementation and Various Uses - http://e-maxx.ru/algo/segment_tree
5. Persistent Segment Tree: -
   1. http://blog.anudeep2011.com/persistent-segment-trees-explained-with-spoj-problems/
   2. II - https://discuss.codechef.com/questions/101647/persistence-made-simple-tutorial
6. problems same as BIT,
7. Problem - http://www.spoj.com/problems/HORRIBLE/
8. Problem - http://www.codechef.com/problems/IDOLS HLD is used as well

Z algorithm

1. Tutorial, Problem - http://codeforces.com/blog/entry/3107
2. Tutorial - https://www.cs.umd.edu/class/fall2011/cmsc858s/Lec02-zalg.pdf
3. Tutorial - https://ivanyu.me/blog/2013/10/15/z-algorithm/
4. problems same as KMP -

Floyd Warshall Algorithm

1. Tutorial, Implementation - http://www.geeksforgeeks.org/dynamic-programming-set-16-floyd-warshall-algorithm/
2. Problem - http://www.spoj.com/problems/AMR11F/
3. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=2356

Sparse Table (LCP, RMQ)

1. Tutorial, Problems - https://www.topcoder.com/community/data-science/data-science-tutorials/range-minimum-query-and-lowest-common-ancestor/
2. Tutorial, Implementation(C++) - http://mayanknatani.wordpress.com/2013/07/15/range-minimum-query/
3. Java implementation - https://sites.google.com/site/indy256/algo/sparse_table_rmq

Heap / Priority Queue / Heapsort

1. Implementation, Explanation - http://www.sourcetricks.com/2011/06/c-heaps.html#.U9z8J_mSzfc
2. Tutorial - http://pages.cs.wisc.edu/~vernon/cs367/notes/11.PRIORITY-Q.html
3. Implementation - http://www.cprogramming.com/tutorial/computersciencetheory/heapcode.html
4. Problem - http://www.codechef.com/problems/REVERSE
5. Chapter from CLRS -

Modular Multiplicative Inverse

1. http://comeoncodeon.wordpress.com/2011/10/09/modular-multiplicative-inverse/

Binomial coefficients (nCr % M)

1. Tutorial - http://discuss.codechef.com/questions/3869/best-known-algos-for-calculating-ncr-m
2. Tutorial - http://fishi.devtail.io/weblog/2015/06/25/computing-large-binomial-coefficients-modulo-prime-non-prime/
3. Paper - https://www.dropbox.com/s/h7665pcqto17pl4/BinCoeff.pdf (Link Not Working),
4. Problem -https://www.codechef.com/problems/SANDWICH

Suffix Automaton

1. Detailed Paper - http://www.cs.nyu.edu/~mohri/pub/nfac.pdf
   1. Tutorial, Implementation (I) - http://www.geeksforgeeks.org/searching-for-patterns-set-5-finite-automata/
   2. Tutorial, Implementation (II) - http://www.geeksforgeeks.org/pattern-searching-set-5-efficient-constructtion-of-finite-automata/
2. Problem - http://www.codechef.com/problems/SUBQUERY
3. Problem - http://www.codechef.com/problems/TSUBSTR
4. Problem - http://www.codechef.com/problems/SSTORY
5. Problem - http://www.codechef.com/problems/MOU1H
6. Tutorial, Implementation - http://e-maxx.ru/algo/suffix_automata

Lowest Common Ancestor

1. Tutorial, Problems - http://www.topcoder.com/tc?d1=tutorials&d2=lowestCommonAncestor&module=Static
2. Paper - http://www14.informatik.tu-muenchen.de/konferenzen/Jass08/courses/1/moufatich/El_Moufatich_Paper.pdf
3. Paper - http://ab.inf.uni-tuebingen.de/people/fischer/lsa.pdf
4. Problem - https://www.codechef.com/LTIME14/problems/TALCA
5. Problem - https://www.spoj.com/problems/LCA/
6. Problem - https://www.codechef.com/problems/TRIPS

Counting Inversions

1. Divide and Conquer - http://www.geeksforgeeks.org/counting-inversions/
2. Segment Tree, - https://www.quora.com/How-to-count-inversions-using-Segment-Tree-of-a-given-array
3. Fenwick Tree - http://pavelsimo.blogspot.in/2012/09/counting-inversions-in-array-using-BIT.html
4. Problem - http://www.codechef.com/problems/DYNAINV

Euclid’s Extended Algorithm

1. http://discuss.codechef.com/questions/20842/a-tutorial-on-the-extended-euclids-algorithm

Suffix Tree

1. Tutorial - http://stackoverflow.com/questions/9452701/ukkonens-suffix-tree-algorithm-in-plain-english
2. Tutorial - http://marknelson.us/1996/08/01/suffix-trees/
3. Intro - http://www.geeksforgeeks.org/pattern-searching-set-8-suffix-tree-introduction/
4. Construction :
   1. • http://www.geeksforgeeks.org/ukkonens-suffix-tree-construction-part-1/
   2. II - http://www.geeksforgeeks.org/ukkonens-suffix-tree-construction-part-2/
5. Implementation - http://marknelson.us/attachments/1996/suffix-trees/stree2006.cpp
6. Implementation - http://www.sanfoundry.com/cpp-program-implement-suffix-tree/
7. Problem - http://www.spoj.com/problems/LCS/
8. Problem - http://www.codechef.com/OCT11/problems/REPSTR
9. Problem - http://www.spoj.com/problems/BEADS/
10. Problem - http://www.codechef.com/problems/TASTR

Dynamic Programming

1. Chapter from CLRS(essential),
2. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/dynamic-programming-from-novice-to-advanced/
3. Problem - http://www.codechef.com/problems/LEPAINT
4. Problem - http://www.codechef.com/problems/COINS
5. Problem - http://www.codechef.com/problems/MARCHA1
6. Problem - http://discuss.codechef.com/questions/47239/frogv-editorial
7. Tutorial - https://www.quora.com/Are-there-any-good-resources-or-tutorials-for-dynamic-programming-DP-besides-the-TopCoder-tutorial
8. Problem - http://www.codechef.com/problems/TSHIRTS
9. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=11566
10. Problem - http://www.spoj.com/problems/SOCOLA/
11. Longest Increasing Subsequence - http://www.geeksforgeeks.org/longest-monotonically-increasing-subsequence-size-n-log-n/
12. Bitmask DP - http://codeforces.com/blog/entry/337
13. Bitmask DP - http://www.ugrad.cs.ubc.ca/~cs490/sec202/notes/dp/DP%202.pdf
14. Optimization - http://codeforces.com/blog/entry/8219
15. Problem - http://www.spoj.com/problems/TRSTAGE/
16. Problem - http://www.spoj.com/problems/LAZYCOWS/
17. Problem - http://www.spoj.com/problems/HIST2/
18. Problem - http://www.spoj.com/problems/MKPAIRS/
19. Problem - http://www.spoj.com/problems/NKLEAVES/
20. Problem - http://www.spoj.com/problems/DRAGON2/
21. Problem - http://codeforces.com/contest/461/problem/B
22. DP on Trees :
    1. • http://www.iarcs.org.in/inoi/online-study-material/topics/dp-trees.php
    2. II - http://www.cs.berkeley.edu/~vazirani/s99cs170/notes/dynamic2.pdf

Basic Data Structures

1. Tutorial - https://www.topcoder.com/community/competitive-programming/tutorials/data-structures/
2. Stack Implementation - https://www.cs.bu.edu/teaching/c/stack/array/
3. Queue Implementation, - http://geeksquiz.com/queue-set-1introduction-and-array-implementation/

Logarithmic Exponentiation

1. http://discuss.codechef.com/questions/20451/a-tutorial-on-fast-modulo-multiplication-exponential-squaring

Graphs

1. Definition, Representation - http://discuss.codechef.com/questions/17801/introduction-to-graphs-definitions-traversal-depth-first-search
2. Definition, Representation - https://www.topcoder.com/community/competitive-programming/tutorials/introduction-to-graphs-and-their-data-structures-section-1/
3. Problem - http://www.codechef.com/problems/DRGHTS
4. Problem - http://www.codechef.com/problems/DIREL

Minimum Spanning Tree

1. Tutorial - https://www.ics.uci.edu/~eppstein/161/960206.html
2. Tutorial, Kruskal’s Implementation - http://www.geeksforgeeks.org/greedy-algorithms-set-2-kruskals-minimum-spanning-tree-mst/
3. Prim’s Implementation - http://www.geeksforgeeks.org/greedy-algorithms-set-5-prims-minimum-spanning-tree-mst-2/
4. Problem - http://www.spoj.com/problems/MST/
5. Problem - http://www.spoj.com/problems/CSTREET/
6. Problem - http://www.spoj.com/problems/BLINNET/
7. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=7921&rd=10765
8. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=7643&rd=12058

Efficient Prime Factorization

1. http://www.geeksforgeeks.org/print-all-prime-factors-of-a-given-number/

Combinatorics

1. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/basics-of-combinatorics/
2. Problem - http://www.codechef.com/problems/BINTOUR
3. Tutorial - http://apps.topcoder.com/forums/?module=Thread&threadID=334598&start=0&mc=13#335550

Union Find/Disjoint Set

1. Tutorial - http://www.cs.cornell.edu/~wdtseng/icpc/notes/graph_part4.pdf
2. Tutorial, Problems - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=disjointDataStructure
3. Problem - http://www.codechef.com/problems/DISHOWN
4. Problem - http://www.spoj.com/problems/BLINNET/
5. Problem - http://www.spoj.com/problems/CHAIN/

Knapsack problem

Solution, Implementation - http://www.geeksforgeeks.org/dynamic-programming-set-10-0-1-knapsack-problem/

Aho-Corasick String Matching Algorithm

1. Tutorial - http://www.cs.sun.ac.za/~lvzijl/courses/rw778/autappl/crous-hw2.pdf
2. Implementation -https://gist.github.com/andmej/1233426
3. Problem - http://www.codechef.com/problems/FAVNUM
4. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=11514&rd=14544
5. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=6017
6. Problem -http://www.spoj.com/problems/WPUZZLES/

Strongly Connected Components

1. Tutorial, Implementation - http://www.geeksforgeeks.org/strongly-connected-components/
2. Tutorial -http://www.cs.berkeley.edu/~vazirani/s99cs170/notes/lec12.pdf
3. Problem - https://www.spoj.com/problems/BOTTOM/
4. Problem - https://www.spoj.com/problems/BREAK/
5. Problem - https://community.topcoder.com/stat?c=problem_statement&pm=8488&rd=11125

Bellman Ford algorithm

1. Tutorial, Implementation - http://www.geeksforgeeks.org/dynamic-programming-set-23-bellman-ford-algorithm/
2. Tutorial, Implementation - http://compprog.wordpress.com/2007/11/29/one-source-shortest-path-the-bellman-ford-algorithm/
3. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=10580
4. Problem - http://codeforces.com/problemset/problem/346/D

Heavy-light Decomposition

1. Tutorial, Problems - http://e-maxx.ru/algo/heavy_light
2. Tutorial, Implementation -http://blog.anudeep2011.com/heavy-light-decomposition/
3. Tutorial - http://wcipeg.com/wiki/Heavy-light_decomposition
4. Implementation - http://apps.topcoder.com/forums/?module=Thread&threadID=796128&start=0&mc=8
5. Implementation - http://pastie.org/private/ozpqitws20ylrj8a57tog
6. Problem - http://www.spoj.com/problems/QTREE6/
7. Problem - http://www.codechef.com/problems/PUSHFLOW
8. Problem - http://www.codechef.com/problems/GERALD2

Convex Hull

1. Tutorial, Jarvis Algorithm Implementation - http://www.geeksforgeeks.org/convex-hull-set-1-jarviss-algorithm-or-wrapping/
2. Tutorial with Graham scan - http://www.geeksforgeeks.org/convex-hull-set-2-graham-scan/
3. Tutorial - https://www.topcoder.com/community/data-science/data-science-tutorials/geometry-concepts-line-intersection-and-its-applications/
4. Implementation - http://stanford.edu/~liszt90/acm/notebook.html#file8
5. Problem - https://www.topcoder.com/stat?c=problem_statement&pm=3996&rd=7224
6. Problem - http://codeforces.com/problemset/problem/166/B
7. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=1960&rd=4670
8. Problem - http://acm.timus.ru/problem.aspx?space=1&num=1185
9. Problem - http://www.spoj.com/problems/BSHEEP/

Line Intersection

1. Tutorial, Implementation - http://www.geeksforgeeks.org/check-if-two-given-line-segments-intersect/
2. Tutorial, Problems - https://www.topcoder.com/community/competitive-programming/tutorials/geometry-concepts-line-intersection-and-its-applications/

Sieve of Erastothenes

1. http://www.geeksforgeeks.org/sieve-of-eratosthenes/

Interval Tree

1. Tutorial, Implementation - http://www.geeksforgeeks.org/interval-tree/
2. Problem - http://www.codechef.com/problems/FLIPCOIN/
3. Problem - https://www.spoj.com/problems/THRBL/
4. Problem - https://www.spoj.com/problems/LITE/
5. Problem - https://www.spoj.com/problems/FREQUENT/
6. Problem - http://www.spoj.com/problems/GSS1/
7. Problem - http://www.spoj.com/problems/GSS3/
8. Tutorial - http://www.dgp.toronto.edu/people/JamesStewart/378notes/22intervals/

Counting Sort

1. http://www.geeksforgeeks.org/counting-sort/

Probabilities

1. https://www.topcoder.com/community/competitive-programming/tutorials/understanding-probabilities/

Matrix Exponentiation

1. Tutorial - http://discuss.codechef.com/questions/2335/building-up-the-recurrence-matrix-to-compute-recurrences-in-ologn-time
2. Tutorial - http://zobayer.blogspot.in/2010/11/matrix-exponentiation.html

Network flow

1. (Max Flow)Tutorial :
   1. I - https://www.topcoder.com/community/competitive-programming/tutorials/maximum-flow-section-1/
   2. II - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=maxFlow2
2. Max Flow(Ford-Fulkerson) Tutorial, Implementation - https://www.geeksforgeeks.org/ford-fulkerson-algorithm-for-maximum-flow-problem/
3. (Min Cut) Tutorial, Implementation - http://www.geeksforgeeks.org/minimum-cut-in-a-directed-graph/
4. (Min Cost Flow)Tutorial :
   1. I, - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=minimumCostFlow1
   2. II - https://www.topcoder.com/community/competitive-programming/tutorials/minimum-cost-flow-part-two-algorithms/
   3. III - https://www.topcoder.com/community/competitive-programming/tutorials/minimum-cost-flow-part-three-applications/
5. Dinic’s Algorithm with Implementation - http://e-maxx.ru/algo/dinic
6. Max flow by Edmonds Karp with Implementation - http://e-maxx.ru/algo/edmonds_karp
7. Problem - http://www.codechef.com/problems/TWOCOMP
8. Problem - http://www.codechef.com/problems/LONGART
9. Problem - http://www.codechef.com/problems/ANUBTT
10. Problem - http://www.codechef.com/problems/ORDERAAM
11. Problem - http://www.codechef.com/problems/PARADE
12. Problem - http://www.codechef.com/problems/CAKE2AM
13. Problem - http://www.spoj.com/problems/EN/
14. Problem - http://www.spoj.com/problems/POTHOLE/
15. Problem - http://www.spoj.com/problems/SCITIES/
16. Problem - http://www.spoj.com/problems/GREED/
17. Problem - http://www.spoj.com/problems/TOURS/
18. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=1931&rd=4709
19. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=2852&rd=5075
20. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=3530&rd=6535

K-d tree

1. Tutorial - http://web.stanford.edu/class/cs106l/handouts/assignment-3-kdtree.pdf
2. Tutorial - http://www.autonlab.org/autonweb/14665/version/2/part/5/data/moore-tutorial.pdf?branch=main&language=en
3. Implementation - http://rosettacode.org/wiki/K-d_tree
4. Problem - http://www.spoj.com/problems/GANNHAT/

Deque

1. http://www.sourcetricks.com/2011/06/c-deque.html#.U--v__mSzfc

Binary Search Tree

1. Tutorial, Implementation - http://www.sourcetricks.com/2011/06/binary-search-trees-in-c.html#.U--wAvmSzfc
2. Searching and Insertion - http://geeksquiz.com/binary-search-tree-set-1-search-and-insertion/
3. Deletion - http://geeksquiz.com/binary-search-tree-set-2-delete/

Quick Select

1. Implementation - http://www.sourcetricks.com/2011/06/quick-select.html#.U_CQ0_mSzfc
2. Implementation - http://rosettacode.org/wiki/Quickselect_algorithm#C.2B.2B

Treap/Cartesian Tree

1. Tutorial(detailed) - http://habrahabr.ru/post/101818/
2. Tutorial, Implementation - http://e-maxx.ru/algo/treap
3. Uses and Problems - http://codeforces.com/blog/entry/3767
4. Problem - http://www.codechef.com/problems/CARDSHUF/
5. Problem - http://www.codechef.com/problems/CHEFC

Game Theory

1. Detailed Paper - http://www.math.ucla.edu/~tom/Game_Theory/comb.pdf
2. Tutorial, Problems - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=algorithmGames
3. Grundy Numbers - http://letuskode.blogspot.ch/2014/08/grundy-numbers.html
4. Tutorial with example problems -
   1. I, - http://www.thelearningpoint.net/home/mathematics/an-introduction-to-game-theory
   2. II, - http://www.thelearningpoint.net/home/mathematics/a-totorial-on-extensive-games-with-problems-and-solutions
   3. III, - http://www.thelearningpoint.net/home/mathematics/bayesian-games---games-with-incomplete-information
   4. IV - http://www.thelearningpoint.net/home/mathematics/repeated-games---tutorial-and-solved-problems
5. Tutorial, Problems - http://www.codechef.com/wiki/tutorial-game-theory
6. Problem - http://www.spoj.com/problems/NGM/
7. Problem - http://www.spoj.com/problems/MCOINS/
8. Problem - http://www.spoj.com/problems/QCJ3/
9. Problem - http://www.spoj.com/problems/RESN04/
10. Problem - http://www.spoj.com/problems/MMMGAME/
11. Problem - http://www.spoj.com/problems/PEBBMOV/
12. Problem - http://www.codechef.com/problems/CHEFBRO
13. Problem - http://www.spoj.com/problems/HUBULLU/
14. Problem - http://www.codechef.com/problems/BIGPIZA
15. Problem - http://codeforces.com/contest/87/problem/C
16. Problem - http://www.spoj.com/problems/CRSCNTRY/
17. Nim - http://codeforces.com/blog/entry/3657

STL (C++)

1. I - https://www.topcoder.com/community/competitive-programming/tutorials/power-up-c-with-the-standard-template-library-part-1/
2. II - https://www.topcoder.com/community/competitive-programming/tutorials/power-up-c-with-the-standard-template-library-part-2/
3. Crash Course - http://community.topcoder.com/tc?module=Static&d1=features&d2=082803

Maximum Bipartite Matching

1. http://www.geeksforgeeks.org/maximum-bipartite-matching/

Manacher’s Algorithm

1. Implementation - http://leetcode.com/2011/11/longest-palindromic-substring-part-ii.html
2. Tutorial - http://tarokuriyama.com/projects/palindrome2.php
3. Tutorial, Implementation - http://tristan-interview.blogspot.in/2011/11/longest-palindrome-substring-manachers.html
4. Tutorial, Implementation - http://e-maxx.ru/algo/palindromes_count
5. Problem - http://acm.timus.ru/problem.aspx?space=1&num=1937
6. Problem - http://www.spoj.com/problems/LPS/
7. Problem - http://www.spoj.com/problems/MSUBSTR/

Miller-Rabin Primality Test

1. http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=primalityTesting
2. Code - http://rosettacode.org/wiki/Miller-Rabin_primality_test#C

Stable Marriage Problem

1. http://www.geeksforgeeks.org/stable-marriage-problem/

Hungarian Algorithm

1. http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=hungarianAlgorithm
2. Tutorial - https://math.uc.edu/~halpern/Linear.progr.folder/Handouts.lp.02/Hungarian.algorithm.pdf

Sweep line Algorithm

1. I - https://www.topcoder.com/tc?module=Static&d1=tutorials&d2=lineSweep
2. II - http://www.geeksforgeeks.org/given-a-set-of-line-segments-find-if-any-two-segments-intersect/

LCP

1. Tutorial, Implementation - http://codeforces.com/blog/entry/12796#comment-175287
2. Tutorial, Implementation - http://e-maxx.ru/algo/suffix_array#7

Gaussian Elimination

1. http://compprog.wordpress.com/2007/12/11/gaussian-elimination/

Pollard Rho Integer Factorization

1. http://www.cs.colorado.edu/~srirams/classes/doku.php/pollard_rho_tutorial
2. problem - http://www.spoj.com/problems/FACT1/

Topological Sorting

1. http://www.geeksforgeeks.org/topological-sorting/

Detecting Cycles in a Graph

1. Directed -
   1. http://www.geeksforgeeks.org/detect-cycle-in-a-graph/
   2. II - http://www.geeksforgeeks.org/union-find/
2. Undirected : http://www.geeksforgeeks.org/detect-cycle-undirected-graph/

Geometry

1. Basics - https://www.topcoder.com/community/competitive-programming/tutorials/geometry-concepts-basic-concepts/
2. Tutorial - http://web.stanford.edu/class/cs97si/09-computational-geometry.pdf

Backtracking

1. N queens problem - http://www.geeksforgeeks.org/backtracking-set-3-n-queen-problem/
2. Tug of War - http://www.geeksforgeeks.org/tug-of-war/
3. Sudoku - http://www.geeksforgeeks.org/backtracking-set-7-suduku/

Eulerian and Hamiltonian Paths

1. Tutorial - http://www.cs.sfu.ca/~ggbaker/zju/math/euler-ham.html#ham
2. Tutorial - http://www.csd.uoc.gr/~hy583/papers/ch14.pdf
3. (Eulerian Path and Cycle)Implementation - http://www.geeksforgeeks.org/eulerian-path-and-circuit/
4. (Hamiltonian Cycle)Implementation - http://www.geeksforgeeks.org/backtracking-set-7-hamiltonian-cycle/

Graph Coloring

1. Tutorial, Implementation - http://algorithm.daqwest.com/search?search=Coloring%20algorithm

Meet in the Middle

1. Tutorial - http://www.infoarena.ro/blog/meet-in-the-middle
2. Implementation - https://sites.google.com/site/indy256/algo/meet-in-the-middle

Arbitrary Precision Integer(BigInt)

1. http://pastebin.com/aQ8NJ197
2. https://github.com/anudeep2011/programming/blob/master/bigint.cpp

Radix Sort

1. http://www.geeksforgeeks.org/radix-sort/

Bucket Sort

1. http://www.geeksforgeeks.org/bucket-sort-2/

Johnson’s Algorithm

1. Tutorial - http://www.geeksforgeeks.org/johnsons-algorithm/
2. Tutorial - http://en.wikipedia.org/wiki/Johnson%27s_algorithm
3. Implementation - https://gist.github.com/ashleyholman/6793360

Maximal Matching in a General Graph

1. Blossom/Edmond’s Algorithm, Implementation - http://e-maxx.ru/algo/matching_edmonds
2. Tutte Matrix - http://e-maxx.ru/algo/tutte_matrix
3. Problem - http://www.codechef.com/problems/SEAGRP

Recursion

1. I, - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=recursionPt1
2. II - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=recursionPt2
3. Towers of Hanoi - http://geeksquiz.com/c-program-for-tower-of-hanoi/
4. with explanation - http://en.wikipedia.org/wiki/Tower_of_Hanoi#Recursive_solution

Inclusion and Exclusion Principle

1. I - http://apps.topcoder.com/forums/?module=Thread&threadID=685138&start=0
2. II - http://e-maxx.ru/algo/inclusion_exclusion_principle

Co-ordinate Compression

1. https://www.quora.com/What-is-coordinate-compression-and-what-is-it-used-for

Sqrt-Decomposition

1. Tutorial - http://e-maxx.ru/algo/sqrt_decomposition
2. Tutorial - http://sysmagazine.com/posts/138946/
3. Problem - http://www.spoj.com/problems/RACETIME/
4. Problem - http://www.codechef.com/problems/GERALD07

Link-Cut Tree

1. Tutorial - http://www.cs.cmu.edu/~sleator/papers/dynamic-trees.pdf
2. Wiki - http://en.wikipedia.org/wiki/Link/cut_tree
3. Tutorial, Implementation - http://www.cs.cmu.edu/~avrim/451f12/lectures/lect1009-linkcut.txt
4. Problem - http://www.codechef.com/problems/QTREE6
5. Problem - http://www.spoj.com/problems/DYNACON1/
6. Problem - http://www.spoj.com/problems/DYNALCA/
7. Problem - http://codeforces.com/contest/117/problem/E

Euler’s Totient Function

1. Explanation, Implementation, Problems - http://e-maxx.ru/algo/euler_function
2. Explanation, Problems - http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=primeNumbers

Burnside Lemma

1. Tutorial - http://e-maxx.ru/algo/burnside_polya
2. Tutorial -http://petr-mitrichev.blogspot.in/2008/11/burnsides-lemma.html
3. Problem - http://community.topcoder.com/stat?c=problem_statement&pm=9975

Edit/Levenshtein Distance

1. Tutorial - https://web.stanford.edu/class/cs124/lec/med.pdf
2. Introduction - http://en.wikipedia.org/wiki/Wagner%E2%80%93Fischer_algorithm
3. Tutorial - http://www.csse.monash.edu.au/~lloyd/tildeAlgDS/Dynamic/Edit/
4. Problem - http://www.codechef.com/problems/SEATSR
5. Problem - http://www.spoj.com/problems/EDIST/

Branch and Bound

1. http://www.academic.marist.edu/~jzbv/algorithms/Branch%20and%20Bound.htm

Math for Competitive Programming

1. http://community.topcoder.com/tc?module=Static&d1=tutorials&d2=math_for_topcoders

Mo’s Algorithm

1. Tutorial and Problems - http://blog.anudeep2011.com/mos-algorithm/

Interview Questions

1. https://shirsh94.medium.com/top-100-interview-programming-questions-that-asks-many-times-5c5bf36449ab
2. https://javaconceptoftheday.com/java-interview-programs-with-solutions/
3. https://codeburst.io/review-these-50-questions-to-crack-your-java-programming-interview-69d03d746b7f
4. https://www.java67.com/2017/08/difference-between-abstract-class-and-interface-in-java8.html
5. https://javarevisited.blogspot.com/2014/07/default-defender-or-extension-method-of-Java8-example-tutorial.html
6. https://javarevisited.blogspot.com/2015/01/how-to-use-lambda-expression-in-place-anonymous-class-java8.html
7. https://www.java67.com/2021/01/spring-data-jpa-interview-questions-answers-java.html
8. https://javarevisited.blogspot.com/2017/12/10-things-java-programmers-should-learn.html#axzz5atl0BngO
9. https://javarevisited.blogspot.com/2021/02/spring-security-interview-questions-answers-java.html
10. https://www.java67.com/2021/01/spring-cloud-interview-questions-with-answers-java.html
11. https://www.java67.com/2021/02/microservices-interview-questions-answers-java-spring.html
12. https://javarevisited.blogspot.com/2021/02/-spring-boot-testing-interview-questions-answers-java.html
13. https://javarevisited.blogspot.com/2021/03/spring-aop-interview-questions-answers.html
14. https://javarevisited.blogspot.com/2015/10/133-java-interview-questions-answers-from-last-5-years.html
15. https://javarevisited.blogspot.com/2014/07/top-50-java-multithreading-interview-questions-answers.html
16. https://javarevisited.blogspot.com/2021/03/top-dynamic-programming-problems-for-coding-interviews.html
17. https://www.java67.com/2016/02/top-20-hibernate-interview-questions.html
18. https://www.baeldung.com/java-collections-interview-questions
19. https://www.baeldung.com/java-type-system-interview-questions
20. https://www.baeldung.com/java-concurrency-interview-questions
21. https://www.baeldung.com/java-classes-initialization-questions
22. https://www.baeldung.com/java-memory-management-interview-questions
23. https://www.baeldung.com/java-generics-interview-questions
24. https://www.baeldung.com/java-flow-control-interview-questions
25. https://www.baeldung.com/java-exceptions-interview-questions
26. https://www.baeldung.com/java-annotations-interview-questions
27. https://www.baeldung.com/spring-interview-questions
28. https://medium.com/@wdn0612
29. https://www.careermatch.com/job-prep/interviews/10-essential-java-interview-questions-and-answers/#:~:text=Tell%20me%20about%20yourself.,-This%20is%20typically&text=A%20sample%20answer%20could%20be,skilled%20at%20working%20in%20teams.
30. https://www.simplilearn.com/java-8-interview-questions-and-answers-article
31. https://www.interviewbit.com/java-8-interview-questions/
32. https://www.interviewbit.com/spring-boot-interview-questions/

Implementations for ADTs

Look at the implementations for various topics in the following books: These books explain some very good concepts in a very good way.

• Algorithhms by Robert Sedgewick, Kevin Wayne
• ArrayResizing
• ReverseArrayIterator
• FixedCapacityStackOfStrings
• ResizingArrayStack

Data Abstraction & Problem Solving with C++

Here is the table of contents from Data Abstraction and Problem Solving with C++

• Link based implementations
• Recursion as a problem solving technique
• Stacks
• Stack implementations
• Lists
• List implementations
• Algorithm efficiency
• Sorting algorithms and their efficiency
• Sorted lists and their implementations
• Queues and priority queues
• Queue implementation
• Trees
• Tree implementations
• Heaps
• Dictionaries and their implementations
• Balanced Search Trees
• Graphs

---

Getting good at ADTs (abstract data types) will eventually get us ready for solving a lot of other problems like bracket balancing, etc. It will also lay a good foundation for trees and graphs.

---

Find an efficient implementation for generating a Fibonacci sequence - do not pay too much attention to the language - language doesn’t matter.

---

Top 75 Programming Interview Questions Answers to Crack Any Coding Job Interview

Hello guys, if you are preparing for your next Programming Job interview and looking for some frequently asked Coding or Programming questions to practice then you have come to the right place. In this article, I am going to share some of the most commonly asked Coding questions from Programming Job interviews (https://javarevisited.blogspot.com/2011/06/top-programming-interview-questions.html). In order to do well on the Coding interview you need practice, you just can’t go there and try to solve the coding problems in limited time, that’s actually one of the most common reasons to fail your programming Job interviews. Sometimes, the interviewer also asks a little bit easier coding questions on a telephonic interview like revering array in place (https://javarevisited.blogspot.com/2015/03/how-to-reverse-array-in-place-in-java.html#axzz5ajxLp4iD) or reversing a string in place (https://www.java67.com/2016/06/how-to-reverse-string-in-place-in-java.html).

Sometimes, when you hear these popular coding questions first time on the interview, you stumble because of nervousness and lack of preparation and that’s where knowledge of popular coding questions is important before going for any programming job interviews.

Most of the coding questions are based upon data structures (https://hackernoon.com/50-data-structure-and-algorithms-interview-questions-for-programmers-b4b1ac61f5b0) like an array, string, linked list, binary tree, etc, but sometimes you also get algorithmic, tricky, logical and scenario-based questions like how to swap two integers without using a temp variable or how to check if two rectangles overlap on each other or not.

That’s why I have divided this list of coding problems into five categories, I mean array-based coding questions, string-based questions, linked list questions, binary tree questions, and others miscellaneous questions, where you will find questions on bit manipulation, design (https://www.java67.com/2018/05/top-20-system-design-interview-questions-answers-programming.html), tricky, logical and other miscellaneous topics.

Btw, good knowledge of Data Structure and Algorithm is essential and even though you will learn a lot of new concepts by solving these questions, I suggest you first refresh your knowledge of Data Structure and Algorithm before attempting these questions by joining a comprehensive course like Data Structures and Algorithms: Deep Dive Using Java on Udemy.

There is no point in attempting these questions if you don’t have sufficient knowledge of data structure and Algorithms.

Top 50 Coding Interview Questions for Programmers

Here is my list of some of the most popular coding questions to crack any programming job interviews.

The questions are more like you find in the popular book Cracking the Coding Interview by Gayle Lakmann Mcdowell, one of the essential books to do well on a Job interview, but more focus on Data Structure and Coding rather than touching every single possible topic required for a programming job interview like SQL (https://www.java67.com/2013/04/10-frequently-asked-sql-query-interview-questions-answers-database.html), UNIX (https://www.java67.com/2012/09/10-linux-and-unix-interview-questions-answers-wipro-tcs-capegemini.html), Database (https://javarevisited.blogspot.com/2018/05/top-5-sql-and-database-courses-to-learn-online.html#axzz5h5DWdBCL), Networking (https://javarevisited.blogspot.com/2014/08/socket-programming-networking-interview-questions-answers-Java.html), etc, for that, you need to read books and you can find many good titles here (https://www.java67.com/2017/06/10-books-to-prepare-technical-coding-job-interviews.html).

We’ll start the list by first exploring array based questions e.g. finding pairs whose sum is given a number and then move to string-based questions, linked list based questions, binary tree questions, and finally tackler other topics.

1. Array-based Programming Interview Questions

If you ask me just one topic to prepare really well for coding interviews, I would pick the array. It’s one of the essential data structures and favorite darling of coding interviews. There are so many popular coding interview questions (https://javarevisited.blogspot.com/2015/02/50-programmer-phone-interview-questions-answers.html) that are based upon the array, some of them are easy and some are tough but you can be sure that you will see some questions based upon array in your next programming job interview.

If you don’t know, an array is a data structure that holds other objects like String, int, float, etc. It holds them in a contiguous location in memory which makes it easily searchable and retrieval in O(1) time using the index.

Insertion and deletion of an array are tough because you cannot change the size of an array once created and you need to create a new array and copy elements from old to new.

Anyway, here are some of the most popular array based coding interview questions for your preparation:

1. How to find the missing number in a given integer array of 1 to 100? (https://javarevisited.blogspot.com/2014/11/how-to-find-missing-number-on-integer-array-java.html)

2. How to find the duplicate number on a given integer array? (https://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

3. How to find the largest and smallest number in an unsorted integer array? (https://www.java67.com/2014/02/how-to-find-largest-and-smallest-number-array-in-java.html)

4. How to find all pairs of integer array whose sum is equal to a given number? (https://javarevisited.blogspot.com/2014/08/how-to-find-all-pairs-in-array-of-integers-whose-sum-equal-given-number-java.html)

5. How to find duplicate numbers in an array if it contains multiple duplicates? (https://javarevisited.blogspot.com/2014/03/3-ways-to-find-first-non-repeated-character-String-programming-problem.html)

6. How to remove duplicates from a given array in Java? (https://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

7. How to sort an integer array in place using QuickSort algorithm? (https://javarevisited.blogspot.com/2014/08/quicksort-sorting-algorithm-in-java-in-place-example.html)

8. How to remove duplicates from an array in place? (https://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

9. How to reverse an array in place in Java? (https://javarevisited.blogspot.com/2013/03/how-to-reverse-array-in-java-int-String-array-example.html)

10. How to find multiple missing numbers in given integer array with duplicates? (https://javarevisited.blogspot.com/2018/04/how-to-find-k-missing-numbers-in-array-java.html#axzz5E2uHdG3w)

I have linked to all the solution but you should try to solve them by yourself before looking at the solution, especially if you have time. That’s the only sure way to learn to program by solving these coding questions.

If you find these questions difficult to solve then once again I suggest you first refresh your knowledge of fundamental data structures like an array by going through a comprehensive course. If you need recommendations, Algorithms, and Data Structures Part 1 and Part 2 by Robert Horvick are two of the best course to start with (https://javarevisited.blogspot.com/2018/11/top-5-data-structures-and-algorithm-online-courses.html#axzz5YFaOvjsh). You will also learn about Big(O) notation and how to calculate time and space complexity.

Array based Programming Interview Questions Answers

If you think these 10 questions from the array are not enough and you are interested in solving more array-based programming problems then you can also check out these 30 array-based coding questions (https://javarevisited.blogspot.com/2015/06/top-20-array-interview-questions-and-answers.html) for more practice.

2. String-based Coding Interview Questions

After array, String is the next popular topic on Programming job interviews, but if you have a good understanding of array then you can easily deal with String programming questions (https://www.java67.com/2018/04/21-string-programming-and-coding-interview-questions-answers.html) because String is nothing but a character array.

The string is implemented differently in a different programming language like in C it’s a NULL-terminated character array but in Java, it’s an object. Though, you can still get access to the underlying array to apply your logic.

Here is a list of some of the frequently asked coding questions which are based on String. Though some of them are quite old, you can still expect this in your programming job interview:

1. How to Print duplicate characters from String? (https://www.java67.com/2014/03/how-to-find-duplicate-characters-in-String-Java-program.html)

2. How to print first non repeated character from String? (https://javarevisited.blogspot.com/2014/03/3-ways-to-find-first-non-repeated-character-String-programming-problem.html)

3. How to reverse a given String using recursion? (https://javarevisited.blogspot.com/2012/01/how-to-reverse-string-in-java-using.html)

4. How to check if a String contains only digits? (https://javarevisited.blogspot.com/2012/10/regular-expression-example-in-java-to-check-String-number.html)

5. How to find duplicate characters in a String? (https://www.java67.com/2014/03/how-to-find-duplicate-characters-in-String-Java-program.html)

6. How to count a number of vowels and consonants in a given String? (https://www.java67.com/2013/11/how-to-count-vowels-and-consonants-in-Java-String-word.html)

7. How to count the occurrence of a given character in String? (https://javarevisited.blogspot.com/2012/12/how-to-count-occurrence-of-character-in-String.html)

8. How to find all permutations of String? (https://javarevisited.blogspot.com/2015/08/how-to-find-all-permutations-of-string-java-example.html)

9. How to reverse words in a given sentence without using any library method? (https://www.java67.com/2015/06/how-to-reverse-words-in-string-java.html)

10. How to check if two String is a rotation of each other? (https://www.java67.com/2017/07/string-rotation-in-java-write-program.html)

11. How to check if given String is Palindrome? (https://www.java67.com/2015/06/how-to-check-is-string-is-palindrome-in.html)

If you want to get most of this article, you better solve these questions without looking at the answers. Only when you stuck and running out-of-time, you can look at the solution.

And, if you find these frequently asked String problems difficult to solve, maybe it’s time to go back to the drawing board and learn the fundamentals of String data structure again. If you need resources then Data Structures and Algorithms Specialization on Coursera is one of the best online resources you can use to make your foundations rock solid.

You can also learn from it by comparing your solution with the solution I have given. It’s not necessarily to be the same but you can learn a lot by comparing them and if you need more practice, here is another list of 20 String algorithm questions (https://javarevisited.blogspot.com/2015/01/top-20-string-coding-interview-question-programming-interview.html).

3. Linked list based Programming Interview Questions

Along with array and string, a linked list is another popular data structure in the programming world as well as on coding interviews. You will find a lot of questions on a linked list like reversing a linked list (https://javarevisited.blogspot.com/2017/03/how-to-reverse-linked-list-in-java-using-iteration-and-recursion.html), adding a new element, removing an element from the middle, etc.

It’s also the counterpart of an array data structure. While array stores elements on contiguous memory location, the linked list stored them at different locations and find them by storing there address. a linked list is made of nodes, an internal data structure which holds the value as well as the address of the next node.

Because of its structure, it’s easier to add and remove elements from the linked list (https://www.java67.com/2016/01/how-to-implement-singly-linked-list-in-java-using-generics-example.html) like on O(1) time if you are adding or removing from the head but the search is equally difficult and takes O(n) time, as you have to literally walk through each element.

Anyway, here is a collection of some of the simple and tricky linked list based coding question for your practice:

1. How to find the middle element of a singly linked list in one pass? (javarevisited.blogspot.sg/2012/12/how-to-find-middle-element-of-linked-list-one-pass.html)

2. How to check if a given linked list contains a cycle? How to find the starting node of the cycle? (https://javarevisited.blogspot.com/2013/05/find-if-linked-list-contains-loops-cycle-cyclic-circular-check.html)

3. How to reverse a linked list? (https://www.java67.com/2016/07/how-to-reverse-singly-linked-list-in-java-example.html)

4. How to reverse a singly linked list without recursion? (https://javarevisited.blogspot.com/2017/03/how-to-reverse-linked-list-in-java-using-iteration-and-recursion.html)

5. How to remove duplicate nodes in an unsorted linked list? (??)

6. How to find the length of a singly linked list? (https://javarevisited.blogspot.com/2016/05/how-do-you-find-length-of-singly-linked.html)

7. How to find the 3rd node from the end in a singly linked list? (https://javarevisited.blogspot.com/2016/07/how-to-find-3rd-element-from-end-in-linked-list-java.html)

8. How do you find the sum of two linked lists using Stack? (https://javarevisited.blogspot.com/2017/07/top-50-java-programs-from-coding-Interviews.html)

You should only look them once you solved the problem on your own or you feel stuck.

A key to solving the linked list is a good understanding of recursion because a linked list is a naturally recursive data structure, for example, if you take one node out of the linked list, the result is another linked list, but many programmers struggle to understand recursion.

That was the case with me as well but after practice and visualizing how recursion really works, I overcome that deficiency. If you are on the same boat, I strongly suggest you go through a visual course like Visualizing Data Structures and Algorithms in Java to learn Recursion and data structure. That will help you a lot in your thought process and problem-solving skills.

Top 75 Programming Interview Questions and Solutions

Once you understand recursion, most of the linked list based problems have an easy recursive solution than their iterative version. And if you need more practice, here is another list of 30 linked list programming questions (https://javarevisited.blogspot.com/2017/07/top-10-linked-list-coding-questions-and.html) for your reference.

4. Binary Tree based Coding Interview Questions

A tree is another popular data structure in the programming world and coding interviews. Unlike array (https://javarevisited.blogspot.com/2016/02/6-example-to-declare-two-dimensional-array-in-java.html) and linked list (https://javarevisited.blogspot.com/2013/07/difference-between-array-and-linked-list-java.html), which are considered linear data structure, a tree is considered a hierarchical data structure and used to arrange information in hierarchical order.

There are a lot of different types of tree e.g. a binary tree, binary search tree, AVL tree, Red-Black tree, etc but Binary and Binary search trees are also known as BST are two of most popular ones and most of the question are based upon them.

Some questions are also based upon theoretical knowledge of tree data structure e.g. finding the height of the tree, finding leaf nodes, checking if the tree is balanced or not, etc, hence you should also spend some time learning the basics, along with practicing coding questions.

Anyway, here is a list of a popular binary tree and binary search tree based coding question to practice before your job interview:

1. Can you write a program to implement a binary search tree? (https://javarevisited.blogspot.com/2015/10/how-to-implement-binary-search-tree-in-java-example.html#axzz4wnEtnNB3)

2. How do you perform Pre-order traversal in a given binary tree? (https://javarevisited.blogspot.com/2016/07/binary-tree-preorder-traversal-in-java-using-recursion-iteration-example.html#axzz5ArdIFI7y)

3. Write a Program to traverse a given binary tree in Pre-order without recursion (https://www.java67.com/2016/07/binary-tree-preorder-traversal-in-java-without-recursion.html)

4. How to perform an In order traversal in a given binary tree? (https://www.java67.com/2016/08/binary-tree-inorder-traversal-in-java.html)

5. How to print all nodes of given binary tree using inorder traversal without recursion (https://www.java67.com/2016/08/binary-tree-inorder-traversal-in-java.html)

6. How to implement a Post-order traversal algorithm? (https://www.java67.com/2016/10/binary-tree-post-order-traversal-in.html)

7. How to traverse a binary tree in Postorder traversal without recursion (https://www.java67.com/2017/05/binary-tree-post-order-traversal-in-java-without-recursion.html)

8. How to Print all leaves of a binary search tree? (https://www.java67.com/2016/09/how-to-print-all-leaf-nodes-of-binary-tree-in-java.html)

9. How to count a number of leaf nodes in a given binary tree? (https://javarevisited.blogspot.com/2016/12/how-to-count-number-of-leaf-nodes-in-java-recursive-iterative-algorithm.html)

10. How to perform a binary search in a given array? (https://javarevisited.blogspot.com/2015/10/how-to-implement-binary-search-tree-in-java-example.html#axzz4wnEtnNB3)

Like an array, linked list, and string questions, I have also linked to all solutions for binary tree questions but you should only look them once you have tried it yourself.

One trick I would like to share with you while solving tree questions is to remember that, similar to a linked list, the tree is also a recursive data structure and most of the tree based problems has an easy recursive solution.

For example, a subtree is also a tree which means you can apply the same steps to subtree can devise a recursive solution. In the above list, many popular tree algorithms e.g. pre-order, post-order, in-order are implemented recursively as well as iterative.

If you don’t feel confident to solve these problems and want to refresh your knowledge of binary tree and other data structure before attempting these questions, then you should check out Data Structures and Algorithms: Deep Dive Using Java from Udemy.

Top 75 Essential Programming Interview Questions to Crack Any Coding Interview

1. Miscellaneous Programming Interview Questions

Even though data structure-based questions make the bulk of the Coding Interview, there are always some questions from topics like sorting algorithms, bit manipulation, software design (https://www.java67.com/2016/07/top-5-object-oriented-design-interview-questions.html), Dynamic Programming (https://www.freecodecamp.org/news/these-are-the-best-free-courses-to-learn-data-structures-and-algorithms-in-depth-4d52f0d6b35a/), and other logical and tricky questions.

In this list below, you will find most of the common searching and sort questions as well as a couple of design and bit manipulation questions.

1. How to implement the Bubble Sort algorithm? (https://javarevisited.blogspot.com/2014/08/bubble-sort-algorithm-in-java-with.html#axzz5ArdIFI7y)

2. How to implement Iterative QuickSort Algorithm? (https://javarevisited.blogspot.com/2016/09/iterative-quicksort-example-in-java-without-recursion.html#axzz5ArdIFI7y)

3. How to implement the Insertion Sort Algorithm? (https://www.java67.com/2014/09/insertion-sort-in-java-with-example.html)

4. How to implement Merge Sort Algorithm? (https://www.java67.com/2018/03/mergesort-in-java-algorithm-example-and.html)

5. How to implement the Bucket Sort Algorithm? (https://javarevisited.blogspot.com/2017/01/bucket-sort-in-java-with-example.html)

6. How to implement the Counting Sort Algorithm? (https://www.java67.com/2017/06/counting-sort-in-java-example.html)

7. How to implement Radix Sort Algorithm? (https://www.java67.com/2018/03/how-to-implement-radix-sort-in-java.html)

8. How to swap two numbers without using the third variable? See SwapIntegersWithoutUsingATempVariable.java

9. How to check if two rectangles overlap with each other? (https://javarevisited.blogspot.com/2016/10/how-to-check-if-two-rectangle-overlap-in-java-algorithm.html)

10. How to check if a given number is a Palindrome? See IntegerPalindrome.java (http://javarevisited.blogspot.sg/2012/12/how-to-check-if-number-is-palindrome-or-not-example.html)

11. How do you check if a given number is an Armstrong number? (https://www.java67.com/2012/07/java-program-to-find-armstrong-numbers.html)

12. How do you find all prime factors of a given number? (https://javarevisited.blogspot.com/2014/05/how-to-find-prime-factors-of-integer-number-java.html#axzz5E2uHdG3w)

13. How do you check if a given number is positive or negative in Java? (https://javarevisited.blogspot.com/2013/01/how-to-check-if-number-is-positive-or-negative-java-example.html#axzz5E2uHdG3w)

14. How to find the largest prime factor of a given integral number? (https://javarevisited.blogspot.com/2015/03/how-to-find-largest-prime-factor-of.html#axzz5E2uHdG3w)

15. Write a Program to print all prime numbers up to a given number? (https://javarevisited.blogspot.com/2012/04/java-program-to-print-prime-numbers-in.html#axzz5E2uHdG3w)

16. Write a Program to print Floyd’s triangle? (https://javarevisited.blogspot.com/2014/12/how-to-print-floyds-triangle-in-java.html)

17. Write a Program to print Pascal’s triangle? (https://www.java67.com/2016/06/how-to-print-pascal-triangle-in-java.html)

18. How to calculate the square root of a given number? (https://javarevisited.blogspot.com/2016/10/how-to-find-square-root-of-number-in-java-algorithm.html#axzz5E2uHdG3w)

19. How to check if the given number is a prime number? (https://www.java67.com/2014/01/how-to-check-if-given-number-is-prime.html)

20. How to implement the Sieve of Eratosthenes Algorithm? (https://javarevisited.blogspot.com/2015/05/sieve-of-Eratosthenes-algorithm-to-generate-prime-numbers-in-java.html)

21. How to add two numbers without using the plus operator in Java? (https://javarevisited.blogspot.com/2013/06/how-to-add-two-integer-numbers-without-plus-arithmetic-operator-java-example.html)

22. Write a Program to subtract two binary numbers? (https://www.java67.com/2018/03/java-program-to-subtract-two-binary-numbers.html)

23. Write a Program to transpose a Matrix? (https://www.java67.com/2016/10/how-to-transpose-matrix-in-java-example.html)

24. Write a Program to add or subtract two Matrices? (https://www.java67.com/2016/10/how-to-add-and-subtract-two-matrices-in-java.html)

25. Write a Program to multiply two Matrices in Java? (https://www.java67.com/2016/10/how-to-multiply-two-matrices-in-java.html)

26. How to calculate the average of all numbers in a given array? (https://www.java67.com/2016/10/how-to-calculate-average-of-all-numbers-in-given-array-java.html)

27. How to check if a given number is even/odd without using an Arithmetic operator? (https://www.java67.com/2012/07/how-to-find-even-and-odd-number-in-java-program.html)

28. Write a Program to find GCD of two numbers using Euclid’s Algorithm? (https://www.java67.com/2012/08/java-program-to-find-gcd-of-two-numbers.html)

29. How to find the number of 1s (the Set bit) in a given Bit Sequence? (https://www.java67.com/2016/01/how-to-count-number-of-1s-in-given-bit-sequence-in-java.html)

30. Write a Program to given Pyramid structure? (https://www.java67.com/2015/10/how-to-print-pyramid-pattern-in-java-example.html)

31. How to find the highest repeating world from a given file in Java? (https://www.java67.com/2015/10/java-program-to-find-repeated-words-and-count.html)

32. How to reverse given Integer in Java? (https://www.java67.com/2015/08/how-to-reverse-integer-in-java-leetcode-solution.html)

33. How to convert a decimal number to binary in Java? (https://www.java67.com/2014/03/decimal-to-binary-conversion-in-java.html)

34. How to check if a given year is a leap year in Java? (https://www.java67.com/2012/12/how-to-check-leap-year-in-java-program.html)

Like previous topics, I have provided links to a solution but you should only look them once you tried to solve the questions yourself. That’s important for learning.

That’s all about some of the essential Programming and Coding Interview questions to crack any programming Job interviews. This list covers the most important topics like an array, string, linked list, binary tree, and several others.

Once you have gone through all these coding questions, you can not only solve them when you see them in the interview but also develop the coding sense and problem-solving ability which will help you to solve new and slightly modified versions of these questions on real programming interview.

AnonymousJuly 26, 2020 at 1:22 AM

This is a great list of problems, but I believe readers should look elsewhere for correct solutions. I haven’t opened all of them, but some of them (e.g. “remove duplicate chars from string”, “find square root of a number”) have some pretty bizarre solutions.

100+ Coding Interview Questions for Programmers

1. How is a bubble sort algorithm implemented? (http://javarevisited.blogspot.sg/2014/08/bubble-sort-algorithm-in-java-with.html#axzz5ArdIFI7y)

2. How is a merge sort algorithm implemented? (http://www.java67.com/2018/03/mergesort-in-java-algorithm-example-and.html)

3. How do you count the occurrence of a given character in a string? (http://javarevisited.blogspot.sg/2012/12/how-to-count-occurrence-of-character-in-String.html)

4. How do you print the first non-repeated character from a string? (http://javarevisited.blogspot.sg/2014/03/3-ways-to-find-first-non-repeated-character-String-programming-problem.html)

5. How do you convert a given String into int like the atoi()? (https://javarevisited.blogspot.com/2011/08/convert-string-to-integer-to-string.html)

6. How do you implement a bucket sort algorithm? (http://javarevisited.blogspot.sg/2017/01/bucket-sort-in-java-with-example.html)

7. How do you implement a counting sort algorithm? (http://www.java67.com/2017/06/counting-sort-in-java-example.html)

8. How do you remove duplicates from an array in place? (http://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

9. How do you reverse an array in place in Java? (http://javarevisited.blogspot.com/2013/03/how-to-reverse-array-in-java-int-String-array-example.html)

10. How are duplicates removed from an array without using any library? (http://javarevisited.blogspot.sg/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

11. How is a radix sort algorithm implemented? (http://www.java67.com/2018/03/how-to-implement-radix-sort-in-java.html)

12. How do you swap two numbers without using the third variable? See SwapIntegersWithoutUsingATempVariable.java

13. How do you check if two rectangles overlap with each other? (http://javarevisited.blogspot.sg/2016/10/how-to-check-if-two-rectangle-overlap-in-java-algorithm.html)

14. How do you find the missing number in a given integer array of 1 to 100? (http://javarevisited.blogspot.com/2014/11/how-to-find-missing-number-on-integer-array-java.html)

15. How do you find the duplicate number on a given integer array? (http://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

16. How do you find duplicate numbers in an array if it contains multiple duplicates? (http://javarevisited.blogspot.com/2014/03/3-ways-to-find-first-non-repeated-character-String-programming-problem.html)

17. Difference between a stable and unstable sorting algorithm? (https://javarevisited.blogspot.com/2017/06/difference-between-stable-and-unstable-algorithm.html)

18. How is an iterative quicksort algorithm implemented? (http://javarevisited.blogspot.sg/2016/09/iterative-quicksort-example-in-java-without-recursion.html#axzz5ArdIFI7y)

19. How do you find the largest and smallest number in an unsorted integer array? (http://java67.blogspot.com/2014/02/how-to-find-largest-and-smallest-number-array-in-java.html)

20. How do you find all pairs of an integer array whose sum is equal to a given number? (http://javarevisited.blogspot.com/2014/08/how-to-find-all-pairs-in-array-of-integers-whose-sum-equal-given-number-java.html)

21. How do you implement an insertion sort algorithm? (http://www.java67.com/2014/09/insertion-sort-in-java-with-example.html)

22. How are duplicates removed from a given array in Java? (http://javarevisited.blogspot.com/2014/01/how-to-remove-duplicates-from-array-java-without-collection-API.html)

23. how to remove the duplicate character from String? (https://javarevisited.blogspot.com/2016/06/how-to-remove-duplicate-characters-from-String-Java.html)

24. How to find the maximum occurring character in given String? (http://javarevisited.blogspot.com/2012/12/how-to-count-occurrence-of-character-in-String.html)

25. How is an integer array sorted in place using the quicksort algorithm? (http://javarevisited.blogspot.com/2014/08/quicksort-sorting-algorithm-in-java-in-place-example.html)

26. How do you reverse a given string in place? (http://www.java67.com/2016/06/how-to-reverse-string-in-place-in-java.html)

27. How do you print duplicate characters from a string? (http://java67.blogspot.sg/2014/03/how-to-find-duplicate-characters-in-String-Java-program.html)

28. How do you find all the permutations of a string? (http://javarevisited.blogspot.com/2015/08/how-to-find-all-permutations-of-string-java-example.html)

29. How can a given string be reversed using recursion? (http://javarevisited.blogspot.sg/2012/01/how-to-reverse-string-in-java-using.html)

30. How do you check if a given string is a palindrome? (http://java67.blogspot.com/2015/06/how-to-check-is-string-is-palindrome-in.html)

31. How do you find the length of the longest substring without repeating characters?

32. How do you find the longest palindromic substring in str?

33. How do you check if a string contains only digits? (http://javarevisited.blogspot.sg/2012/10/regular-expression-example-in-java-to-check-String-number.html)

34. How to convert a sorted list to a binary search tree? (https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/solution/)

35. How do you find duplicate characters in a given string? (http://java67.blogspot.sg/2014/03/how-to-find-duplicate-characters-in-String-Java-program.html)

36. How do you count a number of vowels and consonants in a given string? (http://java67.blogspot.sg/2013/11/how-to-count-vowels-and-consonants-in-Java-String-word.html)

37. How do you reverse words in a given sentence without using any library method? (http://java67.blogspot.com/2015/06/how-to-reverse-words-in-string-java.html)

38. How do you check if two strings are a rotation of each other? (http://www.java67.com/2017/07/string-rotation-in-java-write-program.html)

39. How to convert a byte array to String? (https://javarevisited.blogspot.com/2014/08/2-examples-to-convert-byte-array-to-String-in-Java.html)

40. How do you remove a given character from String? (http://java67.blogspot.com/2013/03/how-to-replace-string-in-java-character-example.html)

41. How is a binary search tree implemented? (http://javarevisited.blogspot.sg/2015/10/how-to-implement-binary-search-tree-in-java-example.html#axzz4wnEtnNB3)

42. How do you perform preorder traversal in a given binary tree? (http://javarevisited.blogspot.sg/2016/07/binary-tree-preorder-traversal-in-java-using-recursion-iteration-example.html#axzz5ArdIFI7y)

43. How do you traverse a given binary tree in preorder without recursion? (http://www.java67.com/2016/07/binary-tree-preorder-traversal-in-java-without-recursion.html)

44. How do you perform an inorder traversal in a given binary tree? (http://www.java67.com/2016/08/binary-tree-inorder-traversal-in-java.html)

45. How do you print all nodes of a given binary tree using inorder traversal without recursion? (http://www.java67.com/2016/08/binary-tree-inorder-traversal-in-java.html)

46. How do you implement a postorder traversal algorithm? (http://www.java67.com/2016/10/binary-tree-post-order-traversal-in.html)

47. How do you traverse a binary tree in postorder traversal without recursion? (http://www.java67.com/2017/05/binary-tree-post-order-traversal-in-java-without-recursion.html)

48. How are all leaves of a binary search tree printed? (http://www.java67.com/2016/09/how-to-print-all-leaf-nodes-of-binary-tree-in-java.html)

49. How do you count a number of leaf nodes in a given binary tree? (http://javarevisited.blogspot.sg/2016/12/how-to-count-number-of-leaf-nodes-in-java-recursive-iterative-algorithm.html)

50. How do you perform a binary search in a given array? (http://javarevisited.blogspot.sg/2015/10/how-to-implement-binary-search-tree-in-java-example.html#axzz4wnEtnNB3)

51. How to Swap two numbers without using the third variable? (http://www.java67.com/2015/08/how-to-swap-two-integers-without-using.html)

52. How to check if two rectangles overlap with each other? (http://javarevisited.blogspot.sg/2016/10/how-to-check-if-two-rectangle-overlap-in-java-algorithm.html)

53. How to check if a given number is a Palindrome? (http://javarevisited.blogspot.sg/2012/12/how-to-check-if-number-is-palindrome-or-not-example.html)

54. How to check if a given number is an Armstrong number? (http://www.java67.com/2012/07/java-program-to-find-armstrong-numbers.html)

55. How to find all prime factors of a given number? (http://javarevisited.blogspot.com/2014/05/how-to-find-prime-factors-of-integer-number-java.html#axzz5E2uHdG3w)

56. How to check if a given number is positive or negative in Java? (http://javarevisited.blogspot.sg/2013/01/how-to-check-if-number-is-positive-or-negative-java-example.html#axzz5E2uHdG3w)

57. How to find the largest prime factor of a given integral number? (http://javarevisited.blogspot.sg/2015/03/how-to-find-largest-prime-factor-of.html#axzz5E2uHdG3w)

58. How to print all prime numbers up to a given number? (http://javarevisited.blogspot.sg/2012/04/java-program-to-print-prime-numbers-in.html#axzz5E2uHdG3w)

59. How to print Floyd’s triangle? (http://javarevisited.blogspot.sg/2014/12/how-to-print-floyds-triangle-in-java.html)

60. How to print Pascal’s triangle? (http://www.java67.com/2016/06/how-to-print-pascal-triangle-in-java.html)

61. How to calculate the square root of a given number? (http://javarevisited.blogspot.sg/2016/10/how-to-find-square-root-of-number-in-java-algorithm.html#axzz5E2uHdG3w)

62. How to check if the given number is a prime number? (http://www.java67.com/2014/01/how-to-check-if-given-number-is-prime.html)

63. How to add two numbers without using the plus operator in Java? (http://javarevisited.blogspot.sg/2013/06/how-to-add-two-integer-numbers-without-plus-arithmetic-operator-java-example.html)

64. How to check if a given number is even/odd without using Arithmetic operator? (http://www.java67.com/2012/07/how-to-find-even-and-odd-number-in-java-program.html)

65. How to print a given Pyramid structure? (http://www.java67.com/2015/10/how-to-print-pyramid-pattern-in-java-example.html)

66. How to find the highest repeating world from a given file in Java? (http://www.java67.com/2015/10/java-program-to-find-repeated-words-and-count.html)

67. How to reverse given Integer in Java? (http://www.java67.com/2015/08/how-to-reverse-integer-in-java-leetcode-solution.html)

68. How to convert a decimal number to binary in Java? (http://www.java67.com/2014/03/decimal-to-binary-conversion-in-java.html)

69. How to check if a given year is a leap year in Java? (http://www.java67.com/2012/12/how-to-check-leap-year-in-java-program.html)

70. Can you implement a Binary search Algorithm without recursion? (https://javarevisited.blogspot.com/2018/06/binary-search-in-java-without-recursion.html)

71. Difference between a stable and unstable sorting algorithm? (https://javarevisited.blogspot.com/2017/06/difference-between-stable-and-unstable-algorithm.html)

72. What is Depth First Search Algorithm for a binary tree?

73. How is an iterative quicksort algorithm implemented? (http://javarevisited.blogspot.sg/2016/09/iterative-quicksort-example-in-java-without-recursion.html#axzz5ArdIFI7y)

74. How do you implement an insertion sort algorithm? (http://www.java67.com/2014/09/insertion-sort-in-java-with-example.html)

75. How is a merge sort algorithm implemented? (http://www.java67.com/2018/03/mergesort-in-java-algorithm-example-and.html)

76. What is the difference between Comparison and Non-Comparison Sorting Algorithms? (https://javarevisited.blogspot.com/2017/02/difference-between-comparison-quicksort-and-non-comparison-counting-sort-algorithms.html)

77. How do implement Sieve of Eratosthenes Algorithms for Prime Number? (https://javarevisited.blogspot.com/2015/05/sieve-of-Eratosthenes-algorithm-to-generate-prime-numbers-in-java.html)

https://www.geeksforgeeks.org/must-coding-questions-company-wise/?ref=leftbar-rightbar

https://www.geeksforgeeks.org/practice-for-cracking-any-coding-interview/?ref=leftbar-rightbar

Link based implementations - mathematical induction

Try to go with topic in geeks for geeks instead of picking problems from all over the place and many websites at random.

• // Self-Balancing Binary Search Tree
• https://www.geeksforgeeks.org/sliding-window-maximum-maximum-of-all-subarrays-of-size-k/
• https://www.geeksforgeeks.org/sum-of-all-subsequences-of-length-k/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/minimum-group-flips-to-make-binary-array-elements-same/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/longest-sub-array-with-maximum-gcd/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/check-if-an-array-is-sorted-and-rotated-using-binary-search/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/split-the-given-string-into-primes-digit-dp/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/efficiently-merging-two-sorted-arrays-with-o1-extra-space-and-onlogn-mlogm/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/minimum-number-of-swaps-required-to-sort-an-array-of-first-n-number/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/minimize-the-maximum-difference-between-adjacent-elements-in-an-array/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/calculate-the-sum-of-gcd-over-all-subarrays/?ref=leftbar-rightbar
• https://www.geeksforgeeks.org/egg-dropping-puzzle-dp-11/
• https://www.geeksforgeeks.org/eggs-dropping-puzzle-binomial-coefficient-and-binary-search-solution/
• https://www.geeksforgeeks.org/program-print-array-pendulum-arrangement/
• geeksforgeeks - Towers of Hanoi concept
• geeksforgeeks - Tree traversals.

http://www-igm.univ-mlv.fr/~lecroq/string/ - EXACT STRING MATCHING ALGORITHMS

Write your own logic for MooshakCatchingCheese.java

Practice:

1. Write a small Java application that uses the String class to input one word at a time and

outputs a complete sentence when a terminating punctuation mark is entered.

1. Write an application similar to the one in exercise 1, but output the words in the sentence in

reverse order.

1. Write the same application using a single StringBuffer object passed to the input

method to collect the words in the sentence.

1. Write a class MutableInteger similar to the Java core class Integer but with the

capability to change the value of the integer. (The Integer class, like the String class, is immutable after it is initialized.)

• https://algorithms.tutorialhorizon.com/
• https://algorithms.tutorialhorizon.com/reverse-a-stack-using-recursion-in-place-without-using-extra-memory/
• https://algorithms.tutorialhorizon.com/sort-a-given-stack-using-temporary-stack/
• https://algorithms.tutorialhorizon.com/sort-a-given-stack-using-recursion/
• https://algorithms.tutorialhorizon.com/depth-first-search-dfs-in-2d-matrix-2d-array-iterative-solution/
• https://algorithms.tutorialhorizon.com/depth-first-search-dfs-in-2d-matrix-2d-array-recursive-solution/
• https://algorithms.tutorialhorizon.com/smallest-number-after-removing-k-digits/
• https://algorithms.tutorialhorizon.com/topological-sort/
• https://algorithms.tutorialhorizon.com/valid-brackets-part-2-stack-method/
• https://algorithms.tutorialhorizon.com/convert-prefix-to-infix-expression/
• https://algorithms.tutorialhorizon.com/convert-infix-to-postfix-expression/
• https://algorithms.tutorialhorizon.com/valid-multiple-parentheses/

Data Structures for Coding Interviews in Java

https://www.educative.io/courses/data-structures-coding-interviews-java?affiliate_id=5073518643380224

1. Complexity Measures

   1. Comparing Algorithms
   2. Example 1: Measuring Time Complexity of a Single Loop Algorithm
   3. Example 2: Time Complexity of an Algorithm With Nested Loops
   4. Introduction to Asymptotic Analysis and Big O
   5. Other Common Asymptotic Notations and Why Big O Trumps Them
   6. Useful Formulae
   7. Common Complexity Scenarios
   8. Challenge 1: Big (O) of Nested Loop with Addition
   9. Solution Review: Big O of a Nested Loop with Addition
   10. Challenge 2: Big (O) of Nested Loop with Subtraction
   11. Solution Review: Big O of a Nested Loop with Subtraction
   12. Challenge 3: Big O of Nested Loop with Multiplication
   13. Solution Review: Big O of Nested Loop with Multiplication
   14. Challenge 4: Nested Loop with Multiplication (Basic)
   15. Solution Review: Nested Loop with Multiplication (Basic)
   16. Challenge 5: Nested Loop with Multiplication (Intermediate)
   17. Solution Review: Nested Loop with Multiplication (Intermediate)
   18. Challenge 6: Nested Loop with Multiplication (Advanced)
   19. Solution Review: Nested Loop with Multiplication (Advanced)
   20. Challenge 7: Nested Loop with Multiplication (Pro)
   21. Solution Review: Nested Loop with Multiplication (Pro)
   22. Complexity Interview Questions

2. Arrays

   1. What is an Array?
   2. Two Dimensional Arrays
   3. Challenge 1: Remove Even Integers from an Array
   4. Solution Review: Remove Even Integers from an Array
   5. Challenge 2: Merge Two Sorted Arrays
   6. Solution Review: Merge Two Sorted Arrays
   7. Challenge 3: Find Two Numbers that Add up to “n”
   8. Solution Review: Find Two Numbers that Add up to “n”
   9. Challenge 4: Array of Products of All Elements Except Itself
   10. Solution Review: Array of Products of All Elements Except Itself
   11. Challenge 5: Find Minimum Value in Array
   12. Solution Review: Find Minimum Value in an Array
   13. Challenge 6: First Non-Repeating Integer in an Array
   14. Solution Review: First Non-Repeating Integer in an Array
   15. Challenge 7: Find Second Maximum Value in an Array
   16. Solution Review: Find Second Maximum Value in an Array
   17. Challenge 8: Right Rotate the Array by One Index
   18. Solution Review: Right Rotate the Array by One Index
   19. Challenge 9: Re-arrange Positive & Negative Values
   20. Solution Review: Re-arrange Positive & Negative Values
   21. Challenge 10: Rearrange Sorted Array in Max/Min Form
   22. Solution Review: Re-arrange Sorted Array in Max/Min Form
   23. Array Interview Questions

3. Linked Lists

   1. What is the Singly Linked List (SLL)?
   2. Basic Linked List Operations
   3. Insertion in a Singly Linked List
   4. Challenge 1: Insertion in a Singly Linked List (insert at End)
   5. Solution Review: Insertion in a Singly Linked List(insert at End)
   6. Insertion in Singly Linked List (Insert After)
   7. Challenge 2: Search in Singly Linked List
   8. Solution Review: Search in a Singly Linked List
   9. Singly Linked List Deletion (Implementation)
   10. Challenge 3: Deletion in Singly Linked List(Delete by Value)
   11. Solution Review: Deletion in Singly Linked List
   12. Linked Lists vs. Arrays
   13. What is a Doubly Linked List (DLL)?
   14. Linked List with Tail
   15. Challenge 4: Find the Length of a Linked List
   16. Solution Review: Find the Length of a Linked List
   17. Challenge 5: Reverse a Linked List
   18. Solution Review: Reverse a Linked List
   19. Challenge 6: Detect Loop in a Linked List
   20. Solution Review: Detect Loop in a Linked List
   21. Challenge 7: Find the Middle Value of a Linked List
   22. Solution Review: Find the Middle Value of a Linked List
   23. Challenge 8: Remove Duplicates from a Linked List
   24. Solution Review: Remove Duplicate from a Linked List
   25. Challenge 9: Union & Intersection of Lists
   26. Solution Review: Union & Intersection of Lists
   27. Challenge 10: Return the Nth node from End
   28. Solution Review: Return the Nth node from End
   29. Challenge 11: Find if Doubly Linked-list is a Palindrome
   30. Solution: Find if a Doubly Linked-list is a Palindrome
   31. Linked list Interview Questions

4. Stack/Queues

   1. What is a Stack?
   2. Stack (Implementation)
   3. What is a Queue?
   4. Queue (Implementation)
   5. Challenge 1: Generate Binary Numbers from 1 to n using a Queue
   6. Solution Review: Generate Binary Numbers from 1 to n using Queue
   7. Challenge 2: Implement Two Stacks using one Array
   8. Solution Review: Implement Two Stacks using one Array
   9. Challenge 3: Reversing the First k Elements of a Queue
   10. Solution Review: Reversing the First k Elements of a Queue
   11. Challenge 4: Implement Queue using Stack
   12. Solution Review: Implement Queue using Stack
   13. Challenge 5: Sort the Values in a Stack
   14. Solution Review: Sort the Values in a Stack
   15. Challenge 6: Evaluate Postfix Expressions using Stacks
   16. Solution Review: Evaluate Postfix Expressions using Stacks
   17. Challenge 7: Next Greater Element using Stack
   18. Solution Review: Next Greater Element using Stack
   19. Challenge 8: Solve a Celebrity Problem using a Stack
   20. Solution Review: Solve a Celebrity Problem using a Stack
   21. Challenge 9: Check for Balanced Parentheses using a Stack
   22. Solution Review: Check for Balanced Parentheses using a Stack
   23. Challenge 10: Create Stack where min() gives minimum in O(1)
   24. Solution Review: Create Stack where min() gives minimum in O(1)
   25. Stack/Queue Interview Questions

5. Graphs

   1. What is a Graph?
   2. Representation of Graphs
   3. Graph Implementation
   4. Complexities of Graph Operations
   5. What is a Bipartite Graph?
   6. Graph Traversal Algorithms
   7. Challenge 1: Implement Breadth First Search
   8. Solution Review: Implement Breadth First Search
   9. Challenge 2: Implement Depth First Search
   10. Solution Review: Implement Depth First Search
   11. Challenge 3: Cycle Detection in a Directed Graph
   12. Solution Review: Cycle Detection in a Directed Graph
   13. Challenge 4: Find “Mother Vertex” in a Directed Graph
   14. Solution Review: Find “Mother Vertex” in a Directed Graph
   15. Challenge 5: Count the Number of Edges in an Undirected Graph
   16. Solution Review: Count the number of Edges in an Undirected Graph
   17. Challenge 6: Check if a Path Exists Between Two Vertices
   18. Solution Review: Check if a Path Exists Between Two Vertices
   19. Challenge 7: Check if a Directed Graph is Tree or not
   20. Solution Review: Check if a Directed Graph is Tree or not
   21. Challenge 8: Find Length of Shortest Path between Two Vertices
   22. Solution Review: Find the Shortest Path between Two Vertices
   23. Challenge 9: Remove Edge from a Directed Graph
   24. Solution Review: Remove Edge from a Directed Graph
   25. Graph Interview Questions

6. Trees

   1. What is a Tree?
   2. Types of Trees
   3. What Makes a Tree Balanced?
   4. What is a Binary Tree?
   5. More on Complete Binary Trees
   6. Skewed Binary Tree
   7. What is a Binary Search Tree (BST)?
   8. Insertion in Binary Search Trees
   9. Insertion in BST (Complete Implementation)
   10. Search in Binary Search Trees (Implementation)
   11. Deletion in Binary Search Trees
   12. Deletion in Binary Search Trees (Implementation)
   13. Pre-Order Traversal in Binary Search Trees
   14. In-Order Traversal in Binary Search Trees
   15. Post-Order Traversal in Binary Search Tree
   16. What is an AVL Tree?
   17. AVL Insertion
   18. AVL Deletion
   19. What is a Red-Black Tree?
   20. Red-Black Tree Insertion
   21. Red-Black Tree Deletion
   22. What is a 2-3 Tree?
   23. 2-3 Insertion
   24. 2-3 Deletion (Case #1)
   25. 2-3 Deletion (Case #2)
   26. 2-3-4 Trees
   27. Overview of Trees
   28. Challenge 1: Find the Minimum Value in a Binary Search Tree
   29. Solution Review: Find the Minimum Value in a Binary Search Tree
   30. Challenge 2: Find kth Maximum Value in a Binary Search Tree
   31. Solution Review: Find kth Maximum Value in a Binary Search Tree
   32. Challenge 3: Find Ancestors of Given Node in Binary Search Tree
   33. Solution Review: Find Ancestors of a Given Node in a Binary Tree
   34. Challenge 4: Find the Height of a Binary Search Tree
   35. Solution Review: Find the Height of a Binary Search Tree
   36. Challenge 5: Find Nodes at “k” Distance from the Root
   37. Solution Review: Find Nodes at “k” Distance from the Root
   38. Tree Interview Questions

7. Trie (Advanced Trees)

   1. What is a Trie?
   2. The Structure of a Trie
   3. Insertion in a Trie
   4. Search in a Trie
   5. Deletion in a Trie
   6. Challenge 1: Total Number of Words in a Trie
   7. Solution Review: Total Number of Words in a Trie
   8. Challenge 2: Find All of the Words in a Trie
   9. Solution Review: Find All of the Words in a Trie
   10. Challenge 3: Sort the Elements of an Array using a Trie.
   11. Solution Review: Sort the Elements of an Array using a Trie.
   12. Challenge 4: Word Formation from a Given Dictionary using a Trie
   13. Solution Review: Word Formation from Given Dictionary using Trie
   14. Trie Interview Questions

8. Heaps

   1. What is a Heap
   2. Why Use Heaps?
   3. Heap Representation in Arrays
   4. Max Heap: Introduction
   5. Max Heap (Implementation)
   6. Min Heap: An Introduction
   7. Min Heap (Implementation)
   8. Challenge 1: Convert a Max-Heap to a Min-Heap
   9. Solution Review: Convert a Max-Heap to a Min-Heap
   10. Challenge 2: Find the k Smallest Elements in an Array
   11. Solution Review: Find the k Smallest Elements in an Array
   12. Challenge 3: Find the k Largest Elements in an Array
   13. Solution Review: Find the k Largest Elements in an Array
   14. Heap Interview Questions

9. Hash Tables

   1. What is a Hash Table?
   2. Hash Functions
   3. Collisions in Hash Tables
   4. Building a Hash Table from Scratch
   5. Add/Remove & Search in a Hash Table (Implementation)
   6. Complete Implementation of Hash Tables
   7. Trie vs Hash Table
   8. HashMap vs HashSet
   9. Challenge 1: Find whether an array is a subset of another array
   10. Solution Review: Find whether an array is a subset of another array
   11. Challenge 2: Check if the given arrays are disjoint
   12. Solution Review: Check if the given arrays are disjoint
   13. Challenge 3: Find symmetric pairs in an Array
   14. Solution Review: Find symmetric pairs in an Array
   15. Challenge 4: Trace the complete path of a journey
   16. Solution Review: Trace the complete path of a journey
   17. Challenge 5: Find two pairs in an Array such that a+b = c+d
   18. Solution Review: Find two pairs in an Array such that a+b = c+d
   19. Challenge 6: Find If a Subarray with a Sum Equal to 0 Exists
   20. Solution Review: Find if a subarray with a sum equal to 0 exists.
   21. Challenge 7: First Non-Repeating Integer in an Array
   22. Solution Review: First Non-Repeating Integer in an Array
   23. Challenge 8: Remove Duplicate from a Linked List using Hashing
   24. Solution Review: Remove Duplicate from Linked List using Hashing
   25. Challenge 9: Union and Intersection of Lists using Hashing
   26. Solution Review: Union and Intersection of Lists using Hashing
   27. Challenge 10: Find Two Numbers that Add up to “n”
   28. Solution Review: Find Two Numbers that Add up to “n”
   29. Hashing Interview Questions

10. Summary of Data Structures

    1. Overview of Linear & Non-Linear Data Structures
    2. Conclusion

Catalog

Topic	Name of the challenge	Java	Go	Rust	Haskell
Abstract data types	Implement Bag Using LinkedList	yes
	Implement Queue Using LinkedList	yes
	Implement Stack Using DoubleLinkedList	yes
	Implement Stack Using LinkedList	yes
	Queue using Stacks - https://www.geeksforgeeks.org/dsa/queue-using-stacks/
	Implement Stack using Queues - https://www.geeksforgeeks.org/dsa/implement-stack-using-queue/
	Implement k stacks in an array - https://www.geeksforgeeks.org/dsa/efficiently-implement-k-stacks-single-array/
	Implement a stack using single queue - https://www.geeksforgeeks.org/dsa/implement-a-stack-using-single-queue/
	Implement stack using priority queue or heap? - https://www.geeksforgeeks.org/dsa/implement-stack-using-priority-queue-or-heap/
	Implement Stack and Queue using Deque - https://www.geeksforgeeks.org/dsa/implement-stack-queue-using-deque/
	Stack using two queues - https://www.geeksforgeeks.org/problems/stack-using-two-queues/1
	Evaluate Postfix Expressions or Reverse Polish Notation (RPN)	yes
	ExpressionEvaluation	yes
	FixedCapacityStack	yes
	FullyParenthesizedArithmeticExpressionEvaluation	yes
	ResizingArrayStack	yes
	ReverseAGivenStack	yes
	ReverseUsingStack.java	yes
Array	ArrayCyclicRotation	yes
	OddNumberOfAnArray	yes
	ArrayResizing	yes
	BirthdayCakeCandles	yes
	DropFirstNElementsOfAnArray	yes
	EquilibriumIndexOfArray	yes
	KadanesAlgorithm.pdf
	LargestSumSubarray	yes
	MaximumAndMinimumElementsInAnArray	yes
	MaximumContiguousSubarraySumProblems.pdf
	MoveNegativeElementsToTheLeft	yes
	SearchForANumberInAnArray	yes
	SequentialParallelAlgorithms4MaxSubarrayProblem	yes
	SimpleArraySum	yes			yes
	SmallestIndexInAnArrayThatHasAllTheElements	yes
	SubarraysWithNegativeSum	yes
	SumOfNaturalNumbersUptoN	yes
	SwapElementsToMakeSumEqual	yes
	Two Sum	yes	yes	yes
	TwoSumFromTwoDifferentArrays	yes
	TwoSumInputArrayIsSorted	yes
	UniqueNumbersInAnArray	yes
	VeryBigArraySum	yes
	WriteArrayBackwards	yes
	Compute number of inversion in an array
	Polygon concavity index
	Flood depth
	Slalom skiing
	Array recovery
Binary Search	Min Max Division
	Nailing Planks
CaterpillarMethod	absolute distinct count of this array
	count distinct slices
	count triangles
	minimal absolute value of a sum of two elements
Counting elements	Frog river one
	Max counters
	Permutation check
	smallest positive number missing from array
Dynamic programming	Min Abs Sum
	Number Solitaire
Euclidean algorithm	GCD
	Chocolates by numbers
	Common prime divisors
Fibonacci numbers	Fib Frog
	Ladder
	Fibonacci Sequence until N		yes
	Fibonacci number at position N		yes
	EvenFibonacciSequence	yes		yes	yes
Fractions	CropRatio.java	yes
	PlusMinus.java	yes
Greedy algorithms	max non overlapping segments
	tie ropes
Hacker Rank	3DSurfaceArea.pdf
	AbsolutePermutation.pdf
	ACM-ICPC-Team.pdf
	AlmostSorted.pdf
	AngryProfessor	yes
	AppendAndDelete.pdf
	AppleAndOrange.pdf	yes			yes
	BeautifulDaysAtTheMovies.java
	BeautifulTriplets.pdf
	BetweenTwoSets	yes			yes
	BiggerIsGreater.pdf
	BirthdayChocolate.pdf
	BonAppetit.pdf
	BreakingTheRecords.pdf				yes
	CatsAndAMouse.pdf
	CavityMap.pdf
	ChocolateFeast.pdf
	CircularArrayRotation.pdf
	ClimbingTheLeaderboard.pdf
	CountingValleys.pdf
	CutTheSticks.pdf
	DayOfTheProgrammer.pdf				yes
	DesignerPdfViewer.pdf
	DivisibleSumPairs.pdf				yes
	DrawingBook.pdf
	ElectronicsShop.pdf
	EmasSupercomputer.pdf
	Encryption.pdf
	EqualiseTheArray.pdf
	ExtraLongFactorials.pdf
	FairRations.pdf
	FindDigits.pdf
	FlatlandSpaceStations.pdf
	FormingAMagicSquare.pdf
	GradingStudents.pdf	yes			yes
	HalloweenSale.pdf
	HappyLadybugs.pdf
	JumpingOnTheClouds.pdf
	JumpingOnTheCloudsRevisited.pdf
	Kangaroo.pdf	yes
	LarrysArray.pdf
	LibraryFine.pdf
	LisasWorkbook.pdf
	ManasaAndStones.pdf
	MatrixLayerRotation.pdf
	MigratoryBirds.pdf				yes
	MinimumDistances.pdf
	ModifiedKaprekarNumbers.pdf
	NonDivisibleSubset.pdf
	OrganizingContainersOfBalls.pdf
	PickingNumbers.pdf
	QueensAttack2.pdf
	RepeatedString.pdf
	SaveThePrisoner.pdf
	SequenceEquation.pdf
	ServiceLane.pdf
	SherlockAndSquares.pdf
	SimpleArraySum	yes
	SockMerchant.pdf				yes
	StrangeCounter.pdf
	TaumAndBday.pdf
	TheBombermanGame.pdf
	TheGridSearch.pdf
	TheHurdleRace.pdf
	TheTimeInWords.pdf
	UtopianTree.pdf
	VeryBigArraySum	yes			yes
	ViralAdvertising.pdf
Higher order functions	11EtaConversion.org				yes
	12ANoteAboutListEfficiency.org				yes
	13CurriedFunctions.hs				yes
	14SomeHigherOrderismIsInOrder.hs				yes
	15MapsAndFilters.hs				yes
	16Lambdas.hs				yes
	17Folds.hs				yes
	18Scans.hs				yes
	19FunctionApplicationWith$.org				yes
	20FunctionComposition01.org				yes
	21FunctionComposition.hs				yes
Hash Maps	IteratingAHashMap	yes
Hash Tables	ChainingHashTableClient	yes
	IteratingAHashTable	yes
	LinearProbingHashTableClient	yes
	SimpleHashTable_Chaining	yes
	SimpleHashTable_LinearProbing	yes
Heap	Heap	yes
	HeapClient	yes
	PriorityQueueClient	yes
Iterations	Binary gap	yes
Linked list (jdk)	JdkLinkedListClient	yes
Linked list (singly linked list)	Sorted Integer LinkedList	yes
	Employee Single Linked List	yes
	Reverse a linked list in place
	Add an element at the middle of the linked list
	Sort a linked list in Java (http://www.java67.com/2016/02/how-to-sort-linkedlist-in-java-example.html)
	Remove Nth Node from the end of a linked list (https://leetcode.com/problems/remove-nth-node-from-end-of-list/solution/)
	Merge two sorted linked list
	Find the middle element of a singly linked list in one pass? (http://javarevisited.blogspot.sg/2012/12/how-to-find-middle-element-of-linked-list-one-pass.html)
	Check if a given linked list contains a cycle? How do you find the starting node of the cycle? (http://javarevisited.blogspot.sg/2013/05/find-if-linked-list-contains-loops-cycle-cyclic-circular-check.html)
	Reverse a linked list? (http://www.java67.com/2016/07/how-to-reverse-singly-linked-list-in-java-example.html)
	Reverse a singly linked list without recursion? (http://javarevisited.blogspot.sg/2017/03/how-to-reverse-linked-list-in-java-using-iteration-and-recursion.html)
	Remove duplicate nodes from an unsorted linked list? (https://www.geeksforgeeks.org/remove-duplicates-from-an-unsorted-linked-list/)
	Remove duplicates from a sorted linked list? (https://leetcode.com/problems/remove-duplicates-from-sorted-list/solution/)
	Find the length of a singly linked list? (http://javarevisited.blogspot.sg/2016/05/how-do-you-find-length-of-singly-linked.html)
	Find the third node from the end in a singly linked list? (http://javarevisited.blogspot.sg/2016/07/how-to-find-3rd-element-from-end-in-linked-list-java.html)
	Find the sum of two linked lists using Stack? (https://www.geeksforgeeks.org/sum-of-two-linked-lists/)
	Find the node at which the intersection of two singly linked lists begins. (https://leetcode.com/problems/intersection-of-two-linked-lists/solution/)
	Given a linked list and a value , partition it such that all nodes less than x come before nodes greater than or equal to x. (https://leetcode.com/problems/partition-list/solution/)
	Check if a given linked list is a palindrome?
	AddTwoNumbersAsALinkedList.txt
	DetectLinkedListCycle.txt
	DetermineIfLinkedListIsPalindrome.txt
	IntersectionOfLinkedLists.txt
	MergeKSortedLinkedLists.txt
	RemoveDuplicateFromLinkedList.txt
	RemoveDuplicatesFromSortedList.txt
	RemovekthLastElementFromLinkedList.txt
	ReverseALinkedList.txt
	RotateLinkedList.txt
	SwapEveryTwoNodesInALinkedList.txt
	Remove all elements from a linked list of integers which matches with given value?
Linked list (doubly linked list)	Employee Double LinkedList	yes
Lists	CompareTriplets	yes
	IteratingAnArrayList	yes
	List Ranges				yes
	Infinite Lists				yes
	List comprehensions				yes
	Tuples				yes
	CountFrequencyOfElementsInAList				yes
	EveryNthElementInAList				yes
	FindFirstDuplicate				yes
	GetTheMiddleElementsOfAList				yes
	IsListSymmetric				yes
	LengthOfAList				yes
	MaxAndMinElementsInAListAndTheirIndices				yes
	RemoveDuplicatesFromList				yes
	UniqueElementsInAList				yes
Maps	Bag Of Words	yes
	Top K Frequent Words	yes
Matrix	Diagonal Difference	yes
	Absolute difference between the sums of its diagonals in a square matrix	yes
	Mooshak Catching Cheese	yes
	There are a lot of helpful methods for matrices here :
	https://introcs.cs.princeton.edu/java/95linear/Matrix.java.html
Numbers	Collatz Sequences	yes
	FindOddNumbersBetweenLAndR.java	yes
	GCDOfNumbersInAnArray.java	yes
	GCDOfTwoNumbersUsingEuclideanAlgorithm.java	yes
	Integer Palindrome	yes
	LargestNumberUnderNDivisibleByAGivenNumber.java	yes
	LCMOfNumbersInAnArray.java	yes
	LCMOfTwoNumbers.java	yes
	MiniMaxSum.java	yes
	ReverseInteger.java	yes
	RightTriange.java	yes
	SumOfAllOddSquaresSmallerThanN.java	yes
	SwapIntegersWithoutUsingATempVariable.java	yes
	Absolute				yes
	AddTwoNumbers				yes
	CalculateEndTimeByStartTimeAndDuration				yes
	CollatzSequences				yes
	Convert list to decimal number				yes
	Double all numbers in a list of integers	yes			yes
	Check if number is even or odd				yes
	Generate a list of even Numbers Till N	yes	yes		yes
	Generate a list of First N Even Numbers	yes	yes		yes
	Generate a list of N even numbers from a given number	yes
	FibonacciSequence	yes		yes	yes
	GenerateAListOfAllEvenNumbersTillN			yes	yes
	GenerateAListOfFirstNEvenNumbers			yes	yes
	Largest number under n divisible by a given number				yes
	LeapYear				yes
	Primes				yes
	RightTriangle				yes
	SumOfAllEvenNumbersInAListOfIntegers				yes
	SumOfAllOddSquaresSmallerThanN				yes
	SumOfEvenValuedFibonacciTermsLessThanMaxValue				yes
	SumOfFirstNMultiplesOf3Or5				yes
	SumOfIntegersInAList				yes
	SumOfMultiplesOf3Or5SmallerThanN				yes
	SumSquareDifference				yes
NumberLineJumps.pdf	NumberLineJumps.hs				yes
Numbers.NumeralSystems	Roman To Decimal	yes
Numbers.NumeralSystems	Decimal To Roman	yes
Leader	Dominator
	EquiLeader
Maximum Slice problem	max double slice sum
	max double slice sum
	max profit
	max slice sum
Prefix sums	CountDiv	yes
	GenomicRangeQuery	yes
	CountDiv	yes
	GenomicRangeQuery	yes
	MaxOrMinAvgSubArrayOfSpecifiedSize	yes
	MinAvgTwoSlice2	yes
	MinAvgTwoSlice3	yes
	MinAvgTwoSlice	yes
	MinAvgTwoSliceProof.pdf	yes
	MushroomPicker	yes
	PassingCars	yes
	PrefixSums	yes
PrimeAndCompositeNumbers	CountFactors
	Flags
	MinPerimeterRectangle
	Peaks
Shunting yard algorithm	TransformAnInfixExpressionToPostfixNotation.java	yes
	Determine if string with multiple parentheses types is properly nested
	Number of fish alive
	Determine if string with single parentheses type is properly nested
	Minimum number of blocks needed to build a wall
SieveOfEratosthenes	CountNonDivisible
	CountSemiprimes
	CountNonDivisible
Sorting	Distinct
	MaxProductOfThree
	NumberOfDiscIntersections
	Triangle
Strings	symmetry point of a string
	depth of a peculiarly represented tree	yes	yes
	reverse characters in a string (for loop)		yes
	reverse characters in a string using linked list (See String Palindrome)	yes
	reverse characters in a string using queue (See String Palindrome)	yes
	longest password
	dwarfs rafting
	BalancedParanthesis	yes
	FizzBuzz	yes	yes	yes
	FizzBuzzMultithreaded	yes
	MostCommonCharacterInString	yes
	Permutations	yes
	ReverseWordsInASentence	yes
	Staircase	yes
	StringPalindrome	yes			yes
	StringReversal	yes
	TimeConversion	yes
	ToCamelCase	yes
	AddLineNumbersToSourceCode.hs				yes
	Anagram.hs				yes
	Angles Of A Clock				yes
	AssessMovies.hs				yes
	CaesarCipher.hs				yes
	CheckIfAllCharsOfAStringAreInAnotherString.hs				yes
	ConvertAStringToLowerCase.hs				yes
	ExamScoreProcessing.hs				yes
	FizzBuzz.hs				yes
	GeneralizedFibonacciSelector.hs				yes
	GetTheMiddleCharactersOfAString.org				yes
	GroupNamesByAlphabets.hs				yes
	ISBNVerifier.hs				yes
	LongestCommonSubsequenceBetweenTwoStrings.hs				yes
	Pagination.hs				yes
	Pangram.hs				yes
	RailFenceCipher.hs				yes
	RemoveSubstringFromAString.hs				yes
	Count the number of words in a file				WordCount.hs
	Count the number of characters in a file				WordCount.hs
Recursion	ChoosingKOutOfNThings	yes
	Factorial	yes			yes
	FindTheKthSmallestValueOfAnArray	yes
	MultiplyingRabbits	yes
	OrganizingAParade	yes
	ProductOfFirstNRealNumbersInArrayUsingRecurson	yes
	ProductOfIntegersInArrayUsingRecursion	yes
	TowersOfHanoi	yes
Search	BinarySearch	yes
	LinearSearch	yes
Sorting	BubbleSort	yes
	BucketSort	yes
	CountingSort	yes
	HeapSort	yes
	InsertionSort	yes
	MergeSort	yes
	Quicksort	yes			yes
	RadixSort	yes
	SelectionSort	yes
	ShellSort	yes
	LinearTimeSort				yes
Sorting by enums	Person.java	yes
	PersonRole.java	yes
Sorting objects	ArraysAndListsComparator.java	yes
	Fruit.java	yes
	NameComparator.java	yes
	QuantityComparator.java	yes
	RatingAndNameComparator.java	yes
	RatingComparator.java	yes
Time complexity	Frog jumps
	Perm missing element
	Tape equilibrium
Trees	BinaryTree_ArithmeticBT.txt
	BinaryTree_BreadthFirstTreeTraversal_ListsByLevel.txt
	BinaryTree_BreadthFirstTreeTraversal.txt
	BinaryTree_BuildBinarySearchTree.txt
	BinaryTree_CeilingOfAGivenElement.txt
	BinaryTree_ChangeSortedListOfNumbersIntoBalancedBinarySearchTree.txt
	BinaryTree_CheckIfItIsValidBST.txt
	BinaryTree_ConvertBinaryTreeToFullBinaryTree.txt
	BinaryTree_CountFullNodesInABinaryTree.txt
	BinaryTree_CountNumberOfNodesInACompleteBinaryTree.txt
	BinaryTree_CountNumberOfNodesInAFullBinaryTree.txt
	BinaryTree_DeleteAnElementFromATree.txt
	BinaryTree_DepthFirstTreeTraversal.txt
	BinaryTree_FindAllDuplicateSubtrees.txt
	BinaryTree_FindIfASubtreeExistsInATree.txt
	BinaryTree_FindTheDeepestNode.txt
	BinaryTree_Flatten.txt
	BinaryTree_FloorOfAnElementInABT.txt
	BinaryTree_HeightAndDepth.txt
	BinaryTree_HeightBalancedBT.txt
	Binary Tree - In-order traversal using O1 space.txt
	BinaryTree_Invert a binary tree in place.txt
	BinaryTree_LargestBSTInABinaryTree.txt
	BinaryTree_LargestPathFromRootToLeaf.txt
	BinaryTree_LevelOfTreeWithMaximumSum.txt
	BinaryTree_LevelOfTreeWithMinimumSum.txt
	BinaryTree_MaximumAndMinimumElementsInATree.txt
	BinaryTree_MinimumPathSumFromRootToLeaf.txt
	BinaryTree_NumberOfCousinsInLevelOrder.txt
	BinaryTree_PathsFromRootToAllLeaves.txt
	BinaryTree_PrintNodesInBoustrophedonOrder.txt
	BinaryTree_PruneByLeafNodeValues.txt
	BinaryTree_ReconstrunctBinaryTreeFromPreorderAndInorderTraversals.txt
	BinaryTree_RemoveNodesToMakeAFullBT.txt
	BinaryTree_ReturnNodeValuesAtAGivenHeight.txt
	BinaryTree_RootToLeafNumbersSummed.txt
	BinaryTree_SearchForAnElementInATree.txt
	BinaryTree_TargetSumFromRootToLeaf.txt
	BinaryTree_UnivalSubtrees.txt
	BinaryTree_ZigZagBinaryTree.txt
	Build a Huffman Tree.txt
	CartesianTree.txt
	Cartesian Tree With a Sequence.txt
	CloneTrees.txt
	Cousins for all nodes in a tree.txt
	CousinsForAllNodes.txt
	GenerateAFiniteTreeInConstantTime.txt
	Horizontal Distance of each node in a tree and Bottom View of the tree with and without horizontal distance.txt
	ImplementLockingInABinaryTree
	LeafSimilarTrees.txt
	Level of the tree with minimum sum.txt
	MakingAHeightBalancedBinarySearchTree.txt
	MaximumPathSumInBinaryTree.txt
	Merge trees by adding nodes at the same positions.txt
	MergeTwoBinaryTreesBasedOnCriteria.txt
	MinimumDepthOfNodesInBinaryTree.txt
	MostFrequentSubtreeSum.txt
	PrintATreeLevelByLevelWithLineBreaks.txt
	RemoveEdgesInATree.txt
	SplitABinarySearchTree.txt
	SymmetricKaryTree.txt
	TreeSerialization.txt
Unidentified	Hilbert maze
	Rectangle builder greater area
	Tree product
	Diamonds count
	Socks laundering
	Tennis tournament
	PersonalizedCoupons	yes
	Geometry (Cube)				yes
	Geometry (Cuboid)				yes
	Geometry (Sphere)				yes
	Algebraic Data Types				yes
	10RecursiveDataStructure.hs				yes
	Association Lists				yes
	Pattern matching				yes
	Guards				yes
Object Oriented and System Design examples	LRU Cache (Hash map and double linked list)	yes
	Vending machine	yes
	Design a Lift system
	Design a Trade Position Aggregator or Portfolio Manager
	Design a Traffic Controller System for a Junction
	Design a URL shortener service

TODO

1. AbsolutePath.txt
2. AddDigits.txt
3. Angry Professor.txt
4. AnIntroToBacktracking.txt
5. Autocompletion.txt
6. Balanced Parantheses Quesions.txt
7. Between two sets.txt
8. BuddyStrings.txt
9. Calculate the fractions positive, negative, and zero elements in an array.txt
10. CharacterMap.txt
11. Rearrange String to make it a palindrome.txt
12. Check if an array is a permutation.txt
13. ChoosingKOutOfNThings.txt
14. CircleOfChainedWords.txt
15. CitySkyline.txt
16. ClosestPointsToOrigin.txt
17. ClosestTo3Sum.txt
18. CollatzSequences.txt
19. CommonCharacters.txt
20. CompareVersionNumbers.txt
21. Compute number of integers divisible by a number.txt
22. ConcatenatedWords.txt
23. ConnectedColorsInAGrid.txt
24. ConsecutiveOnes.txt
25. ConstructAllPossibleBSTs.txt
26. ContiguousSubArrayWithMaximumSum.txt
27. ConvertDecimalNumeralsToRoman.txt
28. ConvertFractionToDecimal.txt
29. ConvertRomanNumeralsToDecimal.txt
30. ConvertToBaseTwo.txt
31. ConvertToHexadecimal.txt
32. CoursePrerequisites.txt
33. CreateASimpleCalculator.txt
34. DecodeString.txt
35. DeepCopyGraph.txt
36. DesignTicTacToe.txt
37. DetermineIfNumber.txt
38. DistributeBonuses.txt
39. Earliest time when a frog can jump to the other side of a river.txt
40. EditDistance.txt
41. Equilibrium index of an array.txt
42. Evaluate expression.txt
43. EvaluatePostfixExpression.txt
44. Even Fibonacci Numbers.txt
45. FallingDominoes.txt
46. FindClosestPoints.txt
47. FindCyclesInAGraph.txt
48. FindDuplicates.txt
49. FindKthLargestElementInAList.txt
50. FindNonDuplicateNumber.txt
51. FindTheKthLargestNumber.txt
52. FindTheKthSmallestValueOfAnArray.txt
53. FindTheNumberOfIslands.txt
54. FindTheSingleElementInAnArrayOfDuplicates.txt
55. FirstAndLastIndicesOfAnElementInSortedArray.txt
56. FirstMissingPositiveInteger.txt
57. FirstRecurringCharacter.txt
58. FixBrackets.txt
59. Split string into parts with equal number of opening and closing brackets.txt
60. FixedCapacityStack.txt
61. FixedPoint.txt
62. FizzBuzzMultithreaded.txt
63. FizzBuzz.txt
64. FlattenDictionary.txt
65. Frog jumps.txt
66. FullyParenthesizedArithmeticExpressionEvaluation.txt
67. GenerateAllIPAddresses.txt
68. Genomic Range Query.txt
69. HIndex.txt
70. HowToPickARandomElementFromAnInfiniteStream.txt
71. HowToSolveAHardProgrammingInterviewQuestion.txt
72. IndexOfLargestNextNumber.txt
73. InorderSuccessor.txt
74. IntersectionOfLists.txt
75. IntersectionOfTwoArrays.txt
76. JumpToTheEnd.txt
77. KaprekarsConstant.txt
78. KClosestElements.txt
79. LargestProductOfThreeElements.txt
80. list.txt
81. LongestCommonPrefix.txt
82. LongestConsecutiveSequence.txt
83. LongestIncreasingSubsequenct.txt
84. LongestPalindromicSubstring.txt
85. LongestSubstringWithKDistinctCharacters.txt
86. LongestSubstrWithoutRepeatingCharacters.txt
87. LookAndSaySequence.txt
88. LowestCommonAncestorOfTwoGivenNodes.txt
89. MajorityElement.txt
90. MakeTheLargestNumber.txt
91. MakingChange.txt
92. MaxAndMinWithMinimumComparisons.txt
93. MaximumInAStact.txt
94. MaximumNonAdjacentSum.txt
95. MaximumProfitFromStocks.txt
96. Max Or Min Avg SubArray Of Specified Size.txt
97. MazePaths.txt
98. MergeListOfNumberIntoRanges.txt
99. MergeOverlappingIntervals.txt
100. Minimal average of any slice containing at least two elements.txt
101. MinimumNumberOfOperations.txt
102. MinimumRemovalsForValidParanthesis.txt
103. MinimumSizeSubarraySum.txt
104. MinRangeNeededToSort.txt
105. MinStack.txt
106. Missing element in a permutation.txt
107. MissingRanges.txt
108. MostCommonCharacterInString.txt
109. MoveZeroes.txt
110. MultiplyingRabbits.txt
111. Multiply.txt
112. Multitasking.txt
113. MyStory.txt
114. NearestPoints.txt
115. Next smallest integer from a sorted array.txt
116. NoAdjacentRepeatingCharacters.txt
117. NonDecreasingArrayWithSingleModification.txt
118. NthFibbonacciNumber.txt
119. NumberOf1Bits.txt
120. NumberOfConnectedComponents.txt
121. NumberOfMeetingRooms.txt
122. NumberOfWaysToClimbStairs.txt
123. OptimizedListSum.txt
124. OrganizingAParade.txt
125. PartitionAList.txt
126. PascalsTriangle.txt
127. Passing cars.txt
128. PerfectNumber.txt
129. PermutationsOfNumbers.txt
130. PhoneNumbers.txt
131. PickingUpChange.txt
132. PlusOne.txt
133. PostorderTraversal.txt
134. PowerFunction.txt
135. Print a staircase of size N.txt
136. ProductOfArrayExceptSelf.txt
137. PythagoreanTriplets.txt
138. QueensOnAChessboard.txt
139. QueueUsingTwoStacks.txt
140. RangeSearchingInASortedList.txt
141. RansonNote.txt
142. RectangleIntersection.txt
143. RemoveAdjacentDuplicateCharacters.txt
144. RemoveCharacterToCreatePalindrome.txt
145. RemoveConsecutiveNodesThatSumToZero.txt
146. RemoveOneLayerOfParanthesis.txt
147. ReshapingMatrix.txt
148. ResizingArrayStack.txt
149. ReverseADirectedGraph.txt
150. ReverseBits.txt
151. Reverse digits of an integer.txt
152. ReverseInteger.txt
153. ReversePolishNotationCalculator.txt
154. ReverseWordsInASentence.txt
155. ReverseWordsInAString.txt
156. ReverseWords.txt
157. RoomScheduling.txt
158. Root to leaf path that sums up to k.txt
159. RotateArray.txt
160. RotateMatrix.txt
161. RunningMedian.txt
162. ScheduleTasks.txt
163. SemanticVersionComparator.txt
164. ShiftedString.txt
165. ShortestDistanceToCharacter.txt
166. ShortestUniquePrefix.txt
167. SmallestNumberThatIsNotASumOfASubsetOfList.txt
168. Smallest positive number missing from a series.txt
169. SortAListWithThreeUniqueNumbers.txt
170. SortAPartiallySortedList.txt
171. SortColors.txt
172. SortedSquareNumbers.txt
173. SortingWindowRange.txt
174. SpiralTraversalOfGrid.txt
175. SpreadsheetColumns.txt
176. SpreadsheetColumnTitle.txt
177. Squareroot.txt
178. StayingOnAChessBoard.txt
179. StringCompression.txt
180. StringToInteger.txt
181. SubArrayWithTargetSum.txt
182. SudokuCheck.txt
183. SumBinaryNumbers.txt
184. Sum of all odd squares that are smaller than 10,000.txt
185. SumOfSquares.txt
186. SwapBits.txt
187. SwapElementsToMakeSumEqual.txt
188. SwapIntegersWithoutUsingATempVariable.txt
189. Tape Equilibrium.txt
190. TheBiggestMistakeInTheCodingInterviewsCandidatesMake.txt
191. TheRealSecretToGettingAJobAtATopCompany.txt
192. ThreeSum.txt
193. TopKFrequenntWords.txt
194. TransformAnInfixExpressionToPostfixNotation.txt
195. TransposeMatrix.txt
196. TrappingRainwater.txt
197. ValidMountainArray.txt
198. WaysToTraverseAGrid.txt
199. Welcome.txt
200. WhyPython.txt
201. WitnessOfTheTallPeople.txt
202. WordConcatenation.txt
203. WordOrderingInADifferentAlphabeticalOrder.txt
204. WordSearch.txt
205. Print array as table.txt
206. Substrings of size K with K distinct chars.txt
207. Find the first circular tour that visits all petrol pumps.txt