interview-preparation-kit

Solutions to all the problems of Interview Preparation Kit on HackerRank, LeetCode problems, and Interviewbit in C++, Java, Python and Javascript.

Question solved

HackerRank

Topic	Question	CPP	JAVA	Python	JavaScript
Warm Up Challenges
	Sock Merchant	Done	Done	Done	Done
	Counting Valleys	Done	Done	Done	Done
	Jumping on the Clouds	Done	Done	Done	Done
	Repeated Strings	Done	Done	Done	Done
Arrays
	Arrays: Left Rotation	Done	Done	Done	Done
	New Year Chaos	Done	Done	Done	Done
	2D Arrays	Done	Done	Done	Done
	Minimum Swaps 2	Done	Done	Done	Done
	Array Manipulation	Done	Done	Done	Done
Dictionaries and Hashmaps
	Ransom Note	Done	Done	Done	Done
	Two Strings	Done	Done	Done	Done
	Frequency Queries	Done	Done	Done	Done
	Sherlock and Anagrams	Done	Done	Done	Done
	Count Triplets	Done	Done	Done	Done
Sorting
	Bubble Sort	Done	Done	Done	Done
	Mark and Toys	Done	Done	Done	Done
	Comparator	Done	Done	Done
	Fraudulent Activity Notifications	Done	Done	Done	Done
	Counting Inversions - Merge Sort	Done	Done	Done	Done
String Manipulation
	Making Anagrams	Done	Done	Done	Done
	Sherlock and Valid String	Done	Done	Done	Done
	Special String Again	Done	Done	Done	Done
	Common Child	Done	Done	Done	Done
	Alternating Characters	Done	Done	Done	Done
Greedy Algorithms
	Luck Balance	Done	Done	Done	Done
	Minimum Absolute Difference in an Array	Done	Done	Done	Done
	Greedy Florist	Done	Done	Done	Done
	Max Min	Done	Done	Done	Done
	Reverse Shuffle Merge	Done	Done	Done	Done
Search
	Minimum Time Required	Done	Done	Done
	Pairs	Done	Done	Done
	Triple Sum	Done	Done	Done
	Maximum Subarray Sum	Done	Done	Done
	Hash Tables: Ice Cream Parlor	Done	Done	Done
	Swap Nodes [Algo]	Done	Done	Done
	Making Candies	Done	Done	Done
Dynamic Programming
	Max Sum Array	Done	Done	Done
	Candies	Done	Done	Done
	Abbreviation	Done	Done	Done
	Decibinary Numbers	Done	Done	Done
Stacks and Queues
	Balanced Brackets	Done	Done	Done
	Queues: A Tale of Two Stacks	Done	Done	Done
	Largest Rectangle	Done	Done	Done
	Min Max Riddle	Done	Done	Done
	Castle on the Grid	Done	Done	Done
	Poisonous Plants	Done	Done	Done
Graphs
	Roads and Libraries	Done	Done	Done
	Find the nearest clone	Done	Done	Done
	BFS: Shortest Reach in a Graph	Done	Done	Done
	DFS: Connected Cell in a Grid	Done	Done	Done
	Matrix		Done	Done
Trees
	Tree: Height of a Binary Tree	Done	Done	Done
	Binary Search Tree: Lowest Common Ancestor	Done	Done	Done
	Tree: Is This a Binary Search Tree?	Done		Done
	Tree: Huffman Decoding	Done	Done	Done
	Balanced Forest	Done	Done	Done
Linked List
	Insert a node at a specific position in a linked list	Done	Done	Done
	Reverse a doubly linked list	Done	Done	Done
	Find Merge Points of Two lists	Done	Done	Done
	Linked Lists: Detect a cycle	Done	Done	Done
	Inserting a Node Into a Sorted Doubly Linked List	Done	Done	Done
Recursion and Backtracking
	Fibonacci Numbers	Done	Done	Done
	Davis' Staircase	Done	Done	Done
	Crossword Puzzle	Done	Done	Done
	Recursive Digit Sum	Done	Done	Done
Miscellaneous
	Flipping Bits	Done	Done	Done
	Time Complexity: Primality	Done	Done	Done
	Friend Circle Queries	Done	Done	Done
	Maximum Xor	Done	Done	Done

LeetCode

Problem #	Problem Name	Difficulty	CPP	JAVA	Python
1	Two Sum	Easy	Done	❌	❌
2	Add Two Numbers	Medium	Done	❌	❌
3	Longest Substring Without Repeating Characters	Medium	❌	❌	Done
4	Median of Two Sorted Arrays	Hard	Done	❌	❌
5	Longest Palindromic Substring	Medium	Done	❌	❌
6	Zigzag Conversion	Medium	Done	❌	❌
7	Reverse Integer	Medium	Done	❌	❌
8	String to Integer (atoi)	Medium	Done	❌	❌
9	Palindrome Number	Easy	Done	Done	Done
10	Regular Expression Matching	Hard	Done	Done	Done
11	Container With Most Water	Medium	Done	Done	Done
12	Integer to Roman	Medium	Done	Done	Done
13	Roman to Integer	Easy	Done	Done	Done
14	Longest Common Prefix	Easy	Done	Done	Done
15	3Sum	Medium	Done	Done	Done
16	3Sum Closest	Medium	Done	Done	Done
17	Letter Combinations of a Phone Number	Medium	Done	Done	Done
18	4Sum	Medium	Done	Done	Done
19	Remove Nth Node From End of List	Medium	Done	Done	Done
20	Valid Parentheses	Easy	Done	Done	Done
21	Merge Two Sorted Lists	Easy	Done	Done	Done
22	Generate Parentheses	Medium	Done	Done	Done
23	Merge k Sorted Lists	Hard	Done	Done	Done
24	Swap Nodes in Pairs	Medium	Done	Done	Done
25	Reverse Nodes in k-Group	Hard	Done	Done	Done
26	Remove Duplicates from Sorted Array	Easy	Done	Done	Done
27	Remove Element	Easy	Done	Done	Done
28	Find the Index of the First Occurrence in a String	Easy	Done	Done	Done
29	Divide Two Integers	Medium	Done	Done	Done
30	Substring with Concatenation of All Words	Hard	Done	Done	Done
31	Next Permutation	Medium	Done	Done	Done
32	Longest Valid Parentheses	Hard	Done	Done	Done
33	Search in Rotated Sorted Array	Medium	Done	Done	Done
34	Find First and Last Position of Element in Sorted Array	Medium	Done	Done	Done
35	Search Insert Position	Easy	Done	Done	Done
36	Valid Sudoku	Medium	Done	Done	Done
37	Sudoku Solver	Hard	Done	Done	Done
38	Count and Say	Medium	Done	Done	Done
39	Combination Sum	Medium	Done	Done	Done
40	Combination Sum II	Medium	Done	Done	Done
41	First Missing Positive	Hard	Done	Done	Done
42	Trapping Rain Water	Hard	Done	Done	Done
43	Multiply Strings	Medium	Done	Done	Done
44	Wildcard Matching	Hard	Done	Done	Done
45	Jump Game II	Medium	Done	Done	Done
46	Permutations	Medium	Done	Done	Done
47	Permutations II	Medium	Done	Done	Done
48	Rotate Image	Medium	Done	Done	Done
49	Group Anagrams	Medium	Done	Done	Done

Interviewbit

Topic	Question	CPP	JAVA	Python	JavaScript
Arrays
	Min Steps in Infinite Grid

Communication channel

https://gitter.im/interview-prep-comm/community

Contribution Guidelines

https://www.hackerrank.com/interview/interview-preparation-kit
Go to this link and solve the problems in C++, Java, Python or Javascript. Save the source file in the corresponding folder in your forked repo. Please update the readme with the completed question's link in the appropriate format, pointing to its address in the master repo, and then make a pull request. Here we are going to expand this project to more questions, ny adding microsoft interview question from GeeksForGeeks . The solution should be in any language from readme table :)