What is it?

A collection of some programs under competetive programming competitions like Hackerrank, CodeChef, SpoJ and Leetcode etc.

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Your code has poor documentation

This repository has working programs that were submitted during competitions as it is. As such they lack comments and proper documentation. However, you can use it as follows.

• Say, you want to look for sieve of eratosthenes's code snippet. Just search in the repo.
• If you want the implementation of the range min-max segment tree, just search segment-tree
• File names usually correspond to the problem title they refer to. So you can search by that.
• Solutions are grouped by languages.

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Who is this for

• Budding programmers delving into the world of competitive programming wanting to see the code in action.
• Myself, to keep on solving problems at all stages of my life.

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Questions by Companies

Google

#	Title	Acceptance	Difficulty	Finished
1	Two Sum	45.50%	Easy	✅
560	Subarray Sum Equals K	43.90%	Medium	✅
68	Text Justification	27.50%	Hard	✅
253	Meeting Rooms II	45.60%	Medium
76	Minimum Window Substring	34.40%	Hard	✅
85	Maximal Rectangle	37.40%	Hard
221	Maximal Square	37.60%	Medium
127	Word Ladder	29.20%	Medium	✅
295	Find Median from Data Stream	43.90%	Hard	✅
394	Decode String	49.60%	Medium
362	Design Hit Counter	63.40%	Medium
528	Random Pick with Weight	43.90%	Medium
843	Guess the Word	46.00%	Hard
1048	Longest String Chain	54.50%	Medium
329	Longest Increasing Path in a Matrix	43.20%	Hard	✅
315	Count of Smaller Numbers After Self	41.40%	Hard
642	Design Search Autocomplete System	44.40%	Hard
410	Split Array Largest Sum	44.40%	Hard
359	Logger Rate Limiter	70.30%	Easy
593	Valid Square	42.90%	Medium
946	Validate Stack Sequences	61.40%	Medium
1153	String Transforms Into Another String	35.90%	Hard
727	Minimum Window Subsequence	41.50%	Hard	✅
399	Evaluate Division	51.30%	Medium
1110	Delete Nodes And Return Forest	66.70%	Medium
722	Remove Comments	34.30%	Medium
809	Expressive Words	47.20%	Medium
729	My Calendar I	51.50%	Medium
1031	Maximum Sum of Two Non-Overlapping Subarrays	57.70%	Medium
752	Open the Lock	51.50%	Medium
679	24 Game	46.10%	Hard
489	Robot Room Cleaner	69.40%	Hard
1146	Snapshot Array	37.00%	Medium
862	Shortest Subarray with Sum at Least K	24.40%	Hard
846	Hand of Straights	53.90%	Medium
659	Split Array into Consecutive Subsequences	43.60%	Medium
346	Moving Average from Data Stream	70.70%	Easy
1438	Longest Continuous Subarray With Abs Diff <= Limit	42.60%	Medium	✅
1088	Confusing Number II	43.50%	Hard	✅
299	Bulls and Cows	42.30%	Easy
951	Flip Equivalent Binary Trees	65.70%	Medium
1376	Time Needed to Inform All Employees	55.20%	Medium	✅
1231	Divide Chocolate	52.20%	Hard
1296	Divide Array in Sets of K Consecutive Numbers	53.20%	Medium
375	Guess Number Higher or Lower II	40.20%	Medium	✅
1140	Stone Game II	62.80%	Medium
1423	Maximum Points You Can Obtain from Cards	41.30%	Medium
833	Find And Replace in String	50.30%	Medium
1345	Jump Game IV	37.40%	Hard
1463	Cherry Pickup II	64.50%	Hard

Amazon

#	Title	Acceptance	Difficulty	Finished
1	Two Sum	45.50%	Easy	✅
200	Number of Islands	46.50%	Medium
2	Add Two Numbers	33.70%	Medium
937	Reorder Data in Log Files	54.30%	Easy
42	Trapping Rain Water	48.50%	Hard	✅
146	LRU Cache	32.80%	Medium
5	Longest Palindromic Substring	29.30%	Medium
23	Merge k Sorted Lists	39.90%	Hard	✅
1192	Critical Connections in a Network	48.60%	Hard
21	Merge Two Sorted Lists	53.20%	Easy
994	Rotting Oranges	47.60%	Medium
56	Merge Intervals	39.10%	Medium	✅
273	Integer to English Words	26.90%	Hard
121	Best Time to Buy and Sell Stock	50.30%	Easy
692	Top K Frequent Words	51.50%	Medium
269	Alien Dictionary	33.30%	Hard
973	K Closest Points to Origin	63.60%	Medium
139	Word Break	39.80%	Medium
253	Meeting Rooms II	45.60%	Medium
297	Serialize and Deserialize Binary Tree	47.10%	Hard
49	Group Anagrams	56.40%	Medium
763	Partition Labels	75.60%	Medium
127	Word Ladder	29.20%	Medium	✅
138	Copy List with Random Pointer	35.80%	Medium
295	Find Median from Data Stream	43.90%	Hard
140	Word Break II	31.50%	Hard
227	Basic Calculator II	36.70%	Medium
79	Word Search	34.90%	Medium
588	Design In-Memory File System	45.30%	Hard
460	LFU Cache	33.90%	Hard
239	Sliding Window Maximum	42.80%	Hard	✅
348	Design Tic-Tac-Toe	54.00%	Medium
472	Concatenated Words	43.30%	Hard
1152	Analyze User Website Visit Pattern	43.60%	Medium
819	Most Common Word	44.60%	Easy
211	Add and Search Word - Data structure design	36.60%	Medium
126	Word Ladder II	21.90%	Hard
240	Search a 2D Matrix II	43.10%	Medium
210	Course Schedule II	39.70%	Medium	✅
642	Design Search Autocomplete System	44.40%	Hard
480	Sliding Window Median	37.00%	Hard
863	All Nodes Distance K in Binary Tree	55.00%	Medium
733	Flood Fill	55.10%	Easy
353	Design Snake Game	33.90%	Medium
694	Number of Distinct Islands	55.70%	Medium
909	Snakes and Ladders	38.30%	Medium
564	Find the Closest Palindrome	19.60%	Hard
1268	Search Suggestions System	63.30%	Medium
1167	Minimum Cost to Connect Sticks	62.60%	Medium
726	Number of Atoms	48.50%	Hard

Facebook

#	Title	Acceptance	Difficulty	Finished
23	Merge k Sorted Lists	39.90%	Hard	✅
238	Product of Array Except Self	59.90%	Medium	✅
56	Merge Intervals	39.10%	Medium	✅
273	Integer to English Words	26.90%	Hard
953	Verifying an Alien Dictionary	54.30%	Easy
560	Subarray Sum Equals K	43.90%	Medium
1249	Minimum Remove to Make Valid Parentheses	62.40%	Medium
269	Alien Dictionary	33.30%	Hard
973	K Closest Points to Origin	63.60%	Medium
31	Next Permutation	32.50%	Medium	✅
415	Add Strings	47.30%	Easy
297	Serialize and Deserialize Binary Tree	47.10%	Hard
88	Merge Sorted Array	39.20%	Easy
215	Kth Largest Element in an Array	54.90%	Medium
199	Binary Tree Right Side View	53.70%	Medium
124	Binary Tree Maximum Path Sum	34.10%	Hard	✅
680	Valid Palindrome II	36.50%	Easy
301	Remove Invalid Parentheses	43.10%	Hard
986	Interval List Intersections	67.20%	Medium
173	Binary Search Tree Iterator	56.10%	Medium
987	Vertical Order Traversal of a Binary Tree	35.40%	Medium
236	Lowest Common Ancestor of a Binary Tree	45.20%	Medium	✅
67	Add Binary	44.10%	Easy
543	Diameter of Binary Tree	48.30%	Easy
528	Random Pick with Weight	43.90%	Medium
438	Find All Anagrams in a String	43.00%	Medium
767	Reorganize String	48.30%	Medium
211	Add and Search Word - Data structure design	36.60%	Medium
158	Read N Characters Given Read4 II - Call multiple times	33.30%	Hard
125	Valid Palindrome	35.80%	Easy
636	Exclusive Time of Functions	51.80%	Medium	✅
340	Longest Substring with At Most K Distinct Characters	43.90%	Hard
621	Task Scheduler	48.60%	Medium
311	Sparse Matrix Multiplication	61.50%	Medium
523	Continuous Subarray Sum	24.60%	Medium
65	Valid Number	15.20%	Hard
278	First Bad Version	35.40%	Easy
721	Accounts Merge	48.30%	Medium
938	Range Sum of BST	81.10%	Easy
785	Is Graph Bipartite?	47.20%	Medium
282	Expression Add Operators	35.40%	Hard
270	Closest Binary Search Tree Value	47.80%	Easy
1060	Missing Element in Sorted Array	54.40%	Medium
670	Maximum Swap	43.30%	Medium
249	Group Shifted Strings	54.50%	Medium
1428	Leftmost Column with at Least a One	46.50%	Medium
398	Random Pick Index	55.50%	Medium
689	Maximum Sum of 3 Non-Overlapping Subarrays	46.00%	Hard
896	Monotonic Array	57.70%	Easy
1026	Maximum Difference Between Node and Ancestor	65.50%	Medium

LinkedIn

#	Title	Acceptance	Difficulty	Finished
53	Maximum Subarray	46.40%	Easy	✅
297	Serialize and Deserialize Binary Tree	47.10%	Hard
380	Insert Delete GetRandom O(1)	47.40%	Medium
127	Word Ladder	29.20%	Medium	✅
364	Nested List Weight Sum II	62.60%	Medium
150	Evaluate Reverse Polish Notation	36.10%	Medium
102	Binary Tree Level Order Traversal	54.20%	Medium
698	Partition to K Equal Sum Subsets	45.00%	Medium
101	Symmetric Tree	46.60%	Easy
339	Nested List Weight Sum	73.60%	Easy
716	Max Stack	42.50%	Easy
149	Max Points on a Line	16.90%	Hard
244	Shortest Word Distance II	52.20%	Medium
605	Can Place Flowers	31.60%	Easy
272	Closest Binary Search Tree Value II	50.30%	Hard
254	Factor Combinations	46.60%	Medium
244	Shortest Word Distance II	48.20%	Medium
364	Nested List Weight Sum II	58.40%	Medium
170	Two Sum III - Data structure design	31.00%	Easy
339	Nested List Weight Sum	69.00%	Easy
272	Closest Binary Search Tree Value II	45.80%	Hard
156	Binary Tree Upside Down	51.60%	Medium
256	Paint House	49.40%	Easy
243	Shortest Word Distance	57.90%	Easy
149	Max Points on a Line	16.00%	Hard
265	Paint House II	42.00%	Hard
65	Valid Number	14.20%	Hard
716	Max Stack	40.40%	Easy
254	Factor Combinations	44.70%	Medium
380	Insert Delete GetRandom O(1)	43.30%	Medium
68	Text Justification	23.90%	Hard	✅
366	Find Leaves of Binary Tree	66.50%	Medium
605	Can Place Flowers	31.10%	Easy

Microsoft

#	Title	Acceptance	Difficulty	Finished
1246	Palindrome Removal	45.90%	Hard
1239	Maximum Length of a Concatenated String with Unique Characters	47.60%	Medium
273	Integer to English Words	26.90%	Hard
428	Serialize and Deserialize N-ary Tree	59.00%	Hard
146	LRU Cache	32.80%	Medium
1156	Swap For Longest Repeated Character Substring	48.70%	Medium
54	Spiral Matrix	33.90%	Medium
212	Word Search II	34.50%	Hard
1236	Web Crawler	64.30%	Medium
828	Count Unique Characters of All Substrings of a Given String	44.80%	Hard
138	Copy List with Random Pointer	35.80%	Medium
545	Boundary of Binary Tree	38.90%	Medium
25	Reverse Nodes in k-Group	41.70%	Hard
348	Design Tic-Tac-Toe	54.00%	Medium
450	Delete Node in a BST	42.90%	Medium
124	Binary Tree Maximum Path Sum	34.10%	Hard	✅
340	Longest Substring with At Most K Distinct Characters	43.90%	Hard
218	The Skyline Problem	34.40%	Hard
200	Number of Islands	46.50%	Medium
358	Rearrange String k Distance Apart	34.70%	Hard
1375	Bulb Switcher III	62.10%	Medium
99	Recover Binary Search Tree	39.30%	Hard
468	Validate IP Address	24.00%	Medium
116	Populating Next Right Pointers in Each Node	44.60%	Medium
41	First Missing Positive	31.80%	Hard	✅
93	Restore IP Addresses	35.30%	Medium
23	Merge k Sorted Lists	39.90%	Hard	✅
103	Binary Tree Zigzag Level Order Traversal	47.00%	Medium
232	Implement Queue using Stacks	49.10%	Easy
1	Two Sum	45.50%	Easy
79	Word Search	34.90%	Medium
1116	Print Zero Even Odd	55.70%	Medium
297	Serialize and Deserialize Binary Tree	47.10%	Hard
4	Median of Two Sorted Arrays	29.40%	Hard
134	Gas Station	38.20%	Medium
207	Course Schedule	42.80%	Medium	✅
445	Add Two Numbers II	54.30%	Medium
105	Construct Binary Tree from Preorder and Inorder Traversal	48.20%	Medium
42	Trapping Rain Water	48.50%	Hard	✅
74	Search a 2D Matrix	36.40%	Medium
151	Reverse Words in a String	21.10%	Medium
102	Binary Tree Level Order Traversal	54.20%	Medium
10	Regular Expression Matching	26.70%	Hard
173	Binary Search Tree Iterator	56.10%	Medium
140	Word Break II	31.50%	Hard
443	String Compression	41.00%	Easy
8	String to Integer (atoi)	15.30%	Medium
148	Sort List	41.80%	Medium	✅
630	Course Schedule III	33.30%	Hard
155	Min Stack	44.20%	Easy
621	Task Scheduler	48.60%	Medium
432	All O`one Data Structure	32.20%	Hard
285	Inorder Successor in BST	40.00%	Medium
240	Search a 2D Matrix II	43.10%	Medium
636	Exclusive Time of Functions	51.80%	Medium	✅
510	Inorder Successor in BST II	57.90%	Medium
716	Max Stack	42.50%	Easy
179	Largest Number	28.50%	Medium
85	Maximal Rectangle	37.40%	Hard
295	Find Median from Data Stream	43.90%	Hard
46	Permutations	63.00%	Medium
133	Clone Graph	34.20%	Medium
89	Gray Code	48.90%	Medium
622	Design Circular Queue	43.50%	Medium
127	Word Ladder	29.20%	Medium	✅
126	Word Ladder II	21.90%	Hard
37	Sudoku Solver	43.20%	Hard
253	Meeting Rooms II	45.60%	Medium
236	Lowest Common Ancestor of a Binary Tree	45.20%	Medium	✅
346	Moving Average from Data Stream	70.70%	Easy
767	Reorganize String	48.30%	Medium
706	Design HashMap	60.90%	Easy
460	LFU Cache	33.90%	Hard
277	Find the Celebrity	41.60%	Medium
419	Battleships in a Board	69.80%	Medium
695	Max Area of Island	62.40%	Medium
48	Rotate Image	56.20%	Medium
722	Remove Comments	34.30%	Medium
380	Insert Delete GetRandom O(1)	47.40%	Medium
75	Sort Colors	47.10%	Medium	✅
457	Circular Array Loop	29.20%	Medium
557	Reverse Words in a String III	69.50%	Easy
49	Group Anagrams	56.40%	Medium
98	Validate Binary Search Tree	27.70%	Medium
679	24 Game	46.10%	Hard
1044	Longest Duplicate Substring	32.00%	Hard
950	Reveal Cards In Increasing Order	74.30%	Medium
128	Longest Consecutive Sequence	44.90%	Hard
56	Merge Intervals	39.10%	Medium	✅
43	Multiply Strings	33.70%	Medium
681	Next Closest Time	44.90%	Medium
1229	Meeting Scheduler	52.30%	Medium
149	Max Points on a Line	16.90%	Hard	✅
121	Best Time to Buy and Sell Stock	50.30%	Easy
21	Merge Two Sorted Lists	53.20%	Easy
17	Letter Combinations of a Phone Number	46.50%	Medium	✅
24	Swap Nodes in Pairs	50.00%	Medium
33	Search in Rotated Sorted Array	34.50%	Medium	✅
773	Sliding Puzzle	59.00%	Hard
129	Sum Root to Leaf Numbers	48.70%	Medium
238	Product of Array Except Self	59.90%	Medium	✅
77	Combinations	54.30%	Medium
528	Random Pick with Weight	43.90%	Medium
53	Maximum Subarray	46.40%	Easy

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Why is it even here

I like to share and showcase all facets of my professional career. Competitive programming is something I extensively did during my college days and I still give it a try whenever time permits.

As such this is a subtle reminder of my capabilites. I'd encourage others to do the same. The check box is motivation enough :)