I challenged myself to solve a coding problem daily, it can either be a newsletter problem sent by daily coding challenge everyday, Leetcode monthly challenge or previously asked questions by big tech.

Daily Coding Problems

#	Company	Description	Solution
31	Google	distance beween two string	solution
33	Microsoft	running median of a sequence	solution
35	Google	strict RGB sequence	solution
37	Google	Power set	solution
38	Microsoft	N queen	solution
41	Facebook	flight iternary	solution
42	Google	subset add to target	solution
47	Amazon	Buy Stock 1	solution
49	Amazon	Maximum Subarray	solution
50	Microsoft	Evaluate expression in Binary tree	solution
51	Facebook	Generates perfectly random	solution
53	Apple	Implement Queue using two stacks	solution
54	DropBox	Sudoku	solution
58	Amazon	Find Minimum in Rotated Sorted Array	solution
60	Facebook	Parition two subset	solution
61	Google	Pow(x, n)	solution
62	Facebook	Way to Reach Bottom matrix	solution
63	Microsoft	find word in matrix	solution
74	Apple	Number of times Element appears	solution
75	Microsoft	Longest Increasing Subsequence	solution
76	Google	Delete column to make it sorted	solution
77	SnapChat	Merge Intervals	solution
78	Facebook	Non Decreasing Array	solution
81	Yelp	Phone Number Combination	solution
86	Google	Minimum parenthesis remove to make it valid	solution
88	ContextLogic	Implement division without using division, multiplication or Modulus	solution
89	LinkedIn	Valid BST	solution
90	Google	Generate random number excluding he lsit	solution
91	DropBox	Dry run code snippet	solution
96	Microsoft	Subsets	solution
98	Courseera	Word Search	solution
99	Microsoft	Longest Consecutive Sequence	solution
100	Google	Minimum steps to cover an infinite grid	solution
101	Alibaba	Return two primes who's sum equals the number	solution
108	Google	Rotate String	solution
109	Cisco	Swap Odd Even bits	solution
113	Google	Reverse word in a String	solution
115	Google	Subtree of Another Tree	solution
122	Zillow	Matrix max coins	solution
125	Google	Two Sum IV - Input is a BST	solution
126	Facebook	Rotate Arrays	solution
146	Facebook	Binary Tree Pruning	solution

Dynamic Programming / Recursion / Back Tracking

#	Description	Solution
1	Airthmetic slices	solution
2	Buy Stock 1	solution
3	Coin change	solution
4	Coin change 2	solution
5	Combination Sum	solution
6	Combination Sum 2	solution
7	Combinations	solution
8	Factorial	solution
9	Fibonnaci	solution
10	Flood fill	solution
11	Frog Jump	solution
12	Generate all substrings	solution
13	Generate all Parenthesis	solution
14	Subsets	solution
15	Letter Combinations of a Phone Number	solution
16	Longest Palindromic Substring	solution
17	Making A Large Island	solution
18	Maximal Square	solution
19	First Missing Positive	solution
20	Minimum Falling Path Sum	solution
21	Minimum Path Sum	solution
22	Number of Longest Increasing Subsequence	solution
23	Paint House	solution
24	House Robber	solution
24	Pow(x, n)	solution
25	Subsets II	solution
26	Triangle	solution
27	N Queen II	solution
28	Expression and Operator	solution
29	Shortest path grid	solution
30	Shortest path grid with obstacles	solution
31	Jump Game	solution
32	Word Search	solution
33	Word Search II	solution
34	Maximum length Subarray with positive product	solution
35	Best Time to Buy & Sell Stock with Cooldown	solution
36	Buy & Sell Stock III	solution
37	Path Sum III	solution
38	3 Sum	solution
39	Rotting Tomatoes	solution
40	Different ways to Add Parenthesis	solution
41	Unique Paths III	solution
42	Iterator for Combinations	solution
43	Largest Divisible Subset	solution
44	Unique Paths	solution
45	Jump Game III	solution
46	Domino and Tromino Tiling	solution
47	Numbers At Most N Given Digit Set	solution
48	Palindrome Partitioning	solution
49	Cherry Pickup	solution
50	Jump Game IV	solution
51	Stone Game IV	solution
52	Predict the winner	solution
53	Word Ladder	solution
54	Remove k digits	solution
55	Encrypted Words	solution
56	Change In Foreign Currency	solution
57	Minimum Operations	solution
58	Max Length Chain	solution
59	Longest Common Subsequence	solution
60	Longest Common Substring	solution
61	Jump Game II	solution
62	Number of Dice Rolls With Target Sum	solution
63	Merge Sort	solution
64	Word Break	solution
65	Minimum Domino Rotations For Equal Row	solution
66	Smallest String With A Given Numeric Value	solution

Trees

#	Description	Solution
1	Two Sum IV - Input is a BST	solution
2	BFS & DFS	solution
3	Binary Tree from List	solution
4	Binary Search Tree	solution
5	BST from List	solution
6	Binary Tree Average Level	solution
7	Connected components undirected graph	solution
8	Count good node	solution
9	Evaluate expression binary tree	solution
10	Left & Right View Tree	solution
11	Maximum product of splitted binary tree	solution
12	N-ary tree level traversal	solution
13	Number of islands	solution
14	Path Sum II	solution
15	Path Sum	solution
16	Redundant connection cycle in graph	solution
17	Smallest subtree with all deepest node	solution
18	Verify Preorder Serialization of a Binary Tree	solution
19	Same Tree	solution
20	Diameter of Binary Tree	solution
21	Construct a BST from preorder traversal	solution
22	Cousin in Binary Tree	solution
23	Binary Tree Paths	solution
24	Count complete Tree Nodes	solution
25	Invert Binary Tree	solution
26	Subtree of Another Tree	solution
27	Maximum Level Sum of a Binary Tree	solution
28	Sum Root to Leaf Numbers	solution
29	Sum of Left Leafs	solution
30	Unique BST	solution
31	Construct Binary Tree from Inorder and Postorder Traversal	solution
32	Delete node ina BST	solution
33	Binary Tree Pruning	solution
34	Binary Tree Tilt	solution
35	Range Sum of BST	solution
36	Populating Next Right Pointers in Each Node	solution
37	Maximum Difference Between Node and Ancestor	solution
38	Sum of Root To Leaf Binary Numbers	solution
39	Insert into a Binary Search Tree	solution
40	All Elements in Two Binary Search Trees	solution
41	Node in Subtree	solution
42	Maximum width of Binary Tree	solution
43	Bottom View of BT	solution
44	Vertical Traversal BT	solution
45	Find Bottom Left Tree Value	solution
46	Lowest Common Ancestor of a Binary Tree	solution
47	Binary Tree Maximum Path Sum	solution
48	Validate Binary Search Tree	solution
49	Lowest Common Ancestor of a Binary Search Tree	solution
50	Search in a Binary Search Tree	solution
51	Trim a Binary Search Tree	solution
52	Convert BST to Greater Tree	solution
53	Increasing Order Search Tre	solution
54	Kth Smallest Element in a BST	solution
55	Recover Binary Search Tree	solution
56	Binary Search Tree Iterator	solution

Arrays

#	Description	Solution
1	Complex Number Multiplication	solution
2	Sum of squares number	solution
3	3 Sum	solution
4	Add string	solution
5	first And Last Element SortedArray	solution
6	Array of doubled pairs	solution
7	Search in Rotated Sorted Array	solution
8	Range Addition II	solution
9	Find Minimum in Rotated Sorted Array	solution
10	Array Nesting	solution
11	Orderly Queue	solution
12	Count special quadruples	solution
13	Slowest key	solution
14	Shifting Letters	solution
15	Max Multiply three numbers	solution
16	Perfect Number	solution
17	Merge Sorted Array	solution
18	Reverse only Letters	solution
19	Longest Turbulent Subarray	solution
20	Spiral Matrix	solution
21	Delete column to make it sorted	solution
22	Merge Intervals	solution
23	Intersection Two Arrays II	solution
24	Remove duplicates sorted array	solution
25	Valid Tic Tac Toe	solution
26	Valid Tic Tac Toe	solution
27	Maximum Length of a Concatenated String with Unique Characters	solution
28	Break a palindrome	solution
28	Tribonnacci Number	solution
29	Unique Email Address	solution
30	Sort Array Parity II	solution
31	Island Perimeter	solution
32	Find All Duplicates in Array	solution
33	Longest Consecutive Sequence	solution
34	Count Primes	solution
35	Minimum steps to cover an infinite grid	solution
36	Return two primes who's sum equals the number	solution
37	Subarray sum equal to k	solution
38	Richest customer wealth	solution
39	Next Greater Element I	solution
40	Reverse word in a String	solution
41	Insert Delete Get Random (1)	solution
42	Shortest Subarray to be Removed to Make Array Sorted	solution
43	Sort Colors	solution
44	Arranging Coins	solution
45	Multiply Strings	solution
46	Generate Pi value using random number between 0 & 1	solution
47	Best Time to Buy and Sell Stock II	solution
48	Minimum Value to Get Positive Step by Step Sum	solution
49	Daily temperatures	solution
50	Kth Smallest Number in Multiplication Table	solution
51	Find All Numbers Disappeared in an Array	solution
52	Hamming Distance	solution
53	Single Element in a Sorted Array	solution
54	Interval List Intersections	solution
55	Accounts Merge	solution
56	Largest Rectangle in Histogram	solution
57	Maximum Product Subarray	solution
58	Remove Duplicate Letters	solution
59	Minimum Cost to Move Chips to The Same Position	solution
60	Partition Equal Subset Sum	solution
61	Consecutive Characters	solution
62	Minimum Absolute Difference	solution
63	Power of Two	solution
64	Remove Covered Intervals	solution
65	K Closest Point to Origin	solution
66	Number Complement	solution
67	Best Sightseeing Pair	solution
68	Smallest Integer Divisible by K	solution
69	Pairs of Songs With Total Durations Divisible by 60	solution
70	Find the Town Judge	solution
71	Car Pooling	solution
72	Robot Bounded In Circle	solution
73	Minimum Number of Arrows to Burst Balloons	solution
74	String to Integer (atoi)	solution
75	Maximize Distance to Closest Person	solution
76	Word pattern	solution
77	Can Place Flowers	solution
78	Gas Stations	solution
79	Sequential Digits	solution
80	Detect Capital	solution
81	Valid Mountain Array	solution
82	Find All Anagrams in a String	solution
83	4 Sum II	solution
84	Contiguous Array	solution
85	Remove Duplicates from Sorted Array II	solution
86	Find the Difference	solution
87	Add Digits	solution
88	K-diff Pairs in an Array	solution
89	Permutation in Strings	solution
90	Continuous Subarray Sum	solution
91	Subarray Sums Divisible by K	solution
92	Minimum Size Subarray Sum	solution
93	Minimum Operations to Reduce X to Zero	solution
94	K Radius Subarray Averages	solution
95	Robot Return to Origin	solution
96	Make Two Arrays Equal by Reversing Sub-arrays	solution
97	Contiguous Subarray	solution
98	Rotational Cipher	solution
99	Minimize Deviation in Array	solution
100	Minimize Permutation	solution
101	Minimum swaps to sort array	solution
102	Slow Sums	solution
103	Element Swapping	solution
104	Seating Arrangements	solution
105	Revenue Milestones	solution
106	Billion Users	solution
107	Balanced Split	solution
108	Counting Triangles	solution
109	Excel Sheet Column Number	solution
110	Total Cache Optimization	solution
111	Compare Version Numbers	solution
112	Summary ranges	solution
113	Counting Bits	solution
114	Largest Triplet Product	solution
115	Is Subsequence	solution
116	Matching Pairs	solution
117	Champagne Tower	solution
118	Earn and Delete	solution
119	Count All Valid Pickup and Delivery Options	solution
120	Merge without extra Space	solution
121	Sort Array By Parity	solution
122	Trapping Rain Water	solution
123	Snapshot Array	solution
124	Count Servers that Communicate	solution
125	Find the Duplicate Number	solution
126	Spiral matrix II	solution
127	Diagonal Traverse	solution
128	Simplify Paths	solution
129	Minimum Remove to Make Valid Parentheses	solution
130	English word to Integer	solution
131	Integer To English Word	solution
132	Score of Parenthesis	solution
133	Partition Labels	solution
134	Broken Calculator	solution
135	Boats to Save People	solution
136	Two City Scheduling	solution
137	Container With Most Water	solution
138	Rotate Image	solution
139	The K Weakest Rows in a Matrix	solution
140	Longest Repeating Character Replacement	solution
141	Valid Anagram	solution
142	Non-overlapping Intervals	solution
143	Insert Intervals	solution
144	Search in Rotated Sorted Array II	solution
145	Search a Matrix 2D	solution
146	Valid Palindrome II	solution
147	Next Permutation	solution
148	3Sum With Multiplicity	solution
149	Last Stone Weight	solution
150	Baseball Game	solution
151	Game of Life	solution
152	Encode and Decode TinyURL	solution
153	Design Underground System	solution
154	Peeking Iterator	solution
155	Path With Minimum Effort	solution
156	Backspace String Compare	solution

Link List

#	Description	Solution
1	Reverse a Link List	solution
2	Split Link List in Parts	solution
3	Flatten a Multilevel Doubly Linked List	solution
4	Swap Nodes in Pairs	solution
5	Remove Linked List Elements	solution
6	Odd Even Linked List	solution
7	Convert Binary Number in a Linked List to Integer	solution
8	Insertion Sort List	solution
9	Reorder List	solution
10	Middle of the Linked List	solution
11	Linked List Random Node	solution
12	Linked List Cycle	solution
13	Linked List Cycle II	solution
14	Add Two Numbers LL	solution
15	Add Two Numbers II LL	solution
16	Merge Two Sorted Lists	solution
17	Merge k Sorted Lists	solution
18	Maximum Sum Of First And last	solution
19	Sort List	solution
20	Remove Duplicates from Sorted List II	solution
21	Rotate List	solution
22	Copy List with Random Pointer	solution
23	Swapping Nodes in a Linked List	solution

Graph

#	Description	Solution
1	Largest Component Size by Common Factor	solution
2	Connected components undirected graph	solution
3	All Paths From Source to Target	solution
4	Course Schedule II	solution
5	Find whether path exists	solution
6	Shortest Path In Binary Matrix	solution
7	Redundant connection cycle in graph	solution
8	Course Schedule	solution
9	Is Graph Bipartite?	solution

Stack and Queues

#	Description	Solution
1	Minimum parenthesis remove to make it valid	solution
2	Min Stack	solution
3	Decode String	solution
4	First non-repeating character in a stream	solution
5	Remove All Adjacent Duplicates in String II	solution
6	Validate Stack Sequence	solution
7	Maximum Frequency Stack	solution
7	Shift 2D Grid	solution

Heap

#	Description	Solution
1	Magical Candy Bag	solution
2	Kth Largest Element in a Stream	solution

Bit Manipulation

#	Description	Solution
1	Bitwise AND of Numbers Range	solution
2	Add Binary	solution

Binary Search

#	Description	Solution
1	Koko Eating Bananas	solution
2	Search Insert Position	solution
3	Search Rotated Array	solution
4	Range Frequency Queries	solution
5	Binary Search	solution
6	Split Array Largest Sum	solution

Trie

#	Description	Solution
1	Stream of Characters	solution
1	Design Add and Search Words Data Structure	solution

How to contribute

Feel free to send me a pull requests, if you spot issues with any of my solutions!

Happy Coding !!!