dmdv / solutions-to-problems

Solutions to coding problems that can occur through high-tier interviews & preparation advices for them.

Most common solutions to problems from interviews of high-tier companies.

Solutions to LeetCode & HackerRank problems.

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The repository is constantly updated when Python, Java or SQL solution to the problem found at LeetCode (mostly) or HackerRank is solved. The solutions to LeetCode problems are posted at the discussion sections in each solved problem's folder.
If the solved LeetCode problem is one of the problems asked by high-tier companies like Adobe, Airbnb, Amazon, Apple, Bloomberg, DE Shaw, Goldman Sachs, Google, LinkedIn, Meta (previously facebook), Microsoft, Netflix, Reddit, Spotify, Tesla], TikTok, Twitter or Uber then that solution for all the companies that had given it as a problem are indentified here while the total number of solved problems per comapny is given here. If the solution wasn't asked to be solved by any of the companies and the solved problem is not glued to any of the high-tier companies; it is just a random problem that was solved.

The progress of my LeetCode account regarding these solutions with additional information like blog post for some solutions giving explanations on them can be found by looking at my LeetCode profile.

The LeetCode solutions of Python are found here, HackerRank solutions of Python are found here while LeetCode solutions implementing Java are found here. Each problem folder has the description of the problem found through pressing the link in README at the respective folder or if it is provided for the particular high-tier company as described above. Some README's in the problem's forder also have the solution and explanation for the problem that redirects to the solution and the explanation to LeetCode post. By pressing on the name of the problem at the Problems and Solutions, Must Do Problems or Google Top you will be redirected to the problem description (1^st column) followed by the solution (2^nd column) while the 3^rd and 4^th columns give time and space complexities of the solution.

Currently, doing Python & a bit of Java problems of LeetCode. HackerRank problems were finished on May and from 28^th of May 2022 am working on solving at least one Python problem from LeetCode daily. The solution is put at the respective LeetCode folder and added to the list of a problems and solutions where companies that provide that problem are identified.

SQL solutions of problems at HackerRank & LeetCode will come this year while they will be updated here for HackerRank and here for LeetCode.

Table of Contents

• Table of contents
• Preparation for Interiews
• Problems and Solutions
• Total Number
• Must Do Problems
• Google Top
• License

Preparation for Interviews

(Back to top)

To prepare for a MAANG interview or a MAANG-level company interview as well as land a job there I highly recommend solving as many problems below as possible and doing one or all of these:

• Joining Hackpack community
• Solving Top LeetCode Problems
• Honing Python Skills
• Looking at possible Multiple Choice Questions

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Problems and Solutions

No.	Question	Solution in IDE	Time Complexity	Space Complexity	Google	Amazon	Apple	Meta	Microsoft	Adobe	Airbnb	Bloomberg	DE Shaw	Goldman Sachs	LinkedIn	Netflix	Reddit	Spotify	Tesla	TikTok	Twitter	Uber	Others
1	01 Matrix	01 Matrix	O(n^2)	O(n^2)
2	3Sum	3Sum	O(n^2)	O(n)																		[]
3	3Sum Closest	3Sum Closest	O(n^2)	O(1)
4	4Sum	4Sum	O(n^2)	O(n)
5	A Number After a Double Reversal	A Number After a Double Reversal	O(n)	O(n)
6	Accounts Merge	Accounts Merge	O(n^2)	O(n^2)
7	Add Binary	Add Binary	O(n)	O(n)
8	Add Digits	Add Digits	O(1)	O(1)
9	Add Strings	Add Strings	O(n)	O(n)
10	Add Two Numbers	Add Two Numbers	O(n)	O(n)
11	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
12	Basic Calculator	Basic Calculator	O(n^2)	O(n)
13	Basic Calculator II	Basic Calculator II	O(n)	O(n)
14	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
15	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
16	Best Time to Buy and Sell Stock III	Best Time to Buy and Sell Stock III	O(n)	O(1)
17	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
18	Binary Search	Binary Search	O(log n)	O(1)
19	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
20	Binary Tree Level Order Traversal	Binary Tree Level Order Traversal	O(n)	O(n)
21	Binary Tree Maximum Path Sum	Binary Tree Maximum Path Sum	O(n)	O(n)
22	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
23	Brace Expansion	Brace Expansion	O(2^n)	O(2^n)
24	Bulls and Cows	Bulls and Cows	O(n)	O(1)
25	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
26	Check If N and Its Double Exist	Check If N and Its Double Exist	O(n)	O(n)
27	Climbing Stairs	Climbing Stairs	O(n)	O(n)						[]				[]				[]
28	Clone Graph	Clone Graph	O(n)	O(n)
29	Coin Change	Coin Change	O(n^2)	O(n)
30	Combination Sum	Combination Sum	O(2^n)	O(n)
31	Combination Sum II	Combination Sum II	O(n^2)	O(n)
32	Combination Sum III	Combination Sum III	O(2^n)	o(n)
33	Combination Sum IV	Combination Sum IV	O(n)	O(n)
34	Construct Binary Tree from Preorder and Inorder Traversal	Construct Binary Tree from Preorder and Inorder Traversal	O(n)	O(n)
35	Container With Most Water	Container With Most Water	O(n)	O(1)
36	Contains Duplicate	Contains Duplicate	O(n)	O(n)
37	Contains Duplicate II	Contains Duplicate II	O(n)	O(n)
38	Contains Duplicate III	Contains Duplicate III	O(n log n)	O(n)
39	Continuous Subarray Sum	Continuous Subarray Sum	O(n)	O(n)
40	Count and Say	Count and say	O(2^n)	O(n)
41	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
42	Count Number of Distinct Integers After Reverse Operations	Count Number of Distinct Integers After Reverse Operations	O(n log n)	O(n)
43	Count Odd Numbers in an Interval Range	Count Odd Numbers in an Interval Range	O(1)	O(1)
44	Count of Smaller Numbers After Self	Count of Smaller Numbers After Self	O(n log n)	O(n)
45	Count Primes	Count Primes	O(n log n)	O(n log n)
46	Count Square Submatrices with All Ones	Count Square Submatrices with All Ones	O(n^2)	O(n^2)
47	Counting Bits	Counting bits	O(n log n)	O(n)
48	Course Schedule	Course Schedule	O(n)	O(n)
49	Course Schedule II	Course Schedule III	O(n)	O(n)
50	Course Schedule III	Course Schedule III	O(n)	O(n)
51	Custom Sort String	Custom Sort String	O(n)	O(n)
52	Daily Temperatures	Daily Temperatures	O(n)	O(n)
53	Encode and Decode Strings	Encode and Decode Strings	O(n)	O(n)
54	Decode Ways	Decode Ways	O(n)	O(n)
55	Design Add and Search Words Data Structure	Design Add and Search Words Data Structure	O(n)	O(n)
56	Destination City	Destination City	O(n)	O(n)
57	Determine if Two Events Have Conflict	Determine if Two Events Have Conflict	O(n log n)	O(1)
58	Different Ways to Add Parentheses	Different Ways to Add Parentheses	O(2^n)	O(2^n)
59	Edit Distance	Edit Distance	O(mn)	O(mn)
60	Encode and Decode Strings	Encode and Decode Strings	O(n)	O(n)
61	Evaluate Division	Evaluate Division	O(n)	O(n)
62	Excel Sheet Column Title	Excel Sheet Column Title	O(log n)	O(log n)
63	Expression Add Operators	Expression Add Operators	O(2^n)	O(2^n)
64	Expression Add Operators	Expression Add Operators	O(2^n)	O2^n)
65	Find All Anagrams in a String	Find All Anagrams in a String	O(n)	O(1)
66	Find All Duplicates in an Array	Find All Duplicates in an Array	O(n)	O(n)
67	Find First and Last Position of Element in Sotrted Array	Find First and Last Position of Element in Sotrted Array	O(log n)	O(log n)
68	Find if Path Exists in Graph	Find if Path Exists in Graph	O(n)	(O(n)
69	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
70	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
71	Find Pivot Index	Find Pivot Index	O(n)	O(1)
72	Find Pivot Index	Find Pivot Index	O(n)	O(1)
73	Find the Difference	Find the Difference	O(n)	O(n)
74	Find the Duplicate Number	Find the Duplicate Number	O(n)	O(1)
75	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String	O(n)	O(1)
76	Find the Minimum Number of Fibonacci Numbers Whose Sum Is K	Find the Minimum Number of Fibonacci Numbers Whose Sum Is K	O(log n)	O(log n)
77	Find Valid Matrix Given Row and Column Sums	Find Valid Matrix Given Row and Column Sums	O(n^2)	O(n^2)
78	First Bad Version	First Bad Version	O(log n)	O(1)
79	First Missing Positive	First Missing Positive	O(n)	O(1)
80	First Unique Character in a String	First Unique Character in a String	O(n)	O(n)
81	Flood Fill	Flood Fill	O(n^2)	O(n^2)
82	Fraction to Recurring Decimal	Fraction to Recurring Decimal	O(n)	O(n)
83	Frog Jump	Frog Jumo	O(n^2)	O(n^2
84	Game of Life	Game of Life	O(n^2)	O(1)
85	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
86	Graph Valid Tree	Graph Valid Tree	O(n)	O(n)
87	Gray Code	Gray Code
88	Group Anagrams	Group Anagrams	O(n)	O(n)
89	Guess Number Higher or Lower	Guess Number Higher or Lower	O(log n)	O(1)
90	H-Index	H-Index	O(n)	O(1)
91	Happy Number	Happy Number	o(log n)	O(log n)
92	High Five	High Five	O(n log n)	O(n)	<
93	House Robber	House Robber	O(n)	O(1)
94	House Robber II	House Robber II	O(n)	O(n)
95	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
96	Insert Interval	Insert Interval	O(n)	O(n)
97	Integer Break	Integer Break	O(n^2)	O(n)
98	Integer to Roman	Integer to Roman	O(1)	O(1)
99	Intersection of Two Ararys	Intersection of Two Ararys	O(n^2)	O(n^2)
100	Intersection of Two Ararys II	Intersection of Two Ararys	O(n)	O(n)
101	Interval List Intersections	Interval List Intersections	O(n^2)	O(n^2)
102	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
103	Is Graph Bipartite?	Is Graph Bipartite?	O(n)	O(n)
104	Island Perimeter	Island Perimeter	O(n^2)	O(1)
105	Isomorphic Strings	Isomorphic Strings	O(n)	O(n)
106	Jump Game	Jump Game	O(n^2)	O(1)
107	Jump Game II	Jump Gmae II	O(n)	O(1)
108	Jump Game III	Jump Game III	O(n)	O(n)
109	K Closest Points to Origin	K Closest Points to Origin	O(n log n)	O(n)
110	Kill Process	Kill Process	O(n)	O(n)
111	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
112	Kth Smallest Element in a BST	Kth Smallest Element in a BST	O(n)	O(n)
113	Largest Number	Largest Number	O(log n)	O(n)
114	Largest Rectangle in Histogram	Largest Rectangle in Histogram.	O(n)	O(n)
115	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
116	Linked List Cycle	Linked List Cycle	O(n)	O(n)
117	Longest Common Prefix	Longest Common Prefix	O(n)	O(1)
118	Longest Common Subsequence	Longest Common Subsequence	O(n)	O(n)
119	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
120	Longest Increasing Path in a Matrix	Longest Increasing Path in a Matrix	O(n^2)	O(n^2)
121	Longest Increasing Subsequence	Longest Increasing Subsequence	O(n^2)	O(n)
122	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
123	Longest Repeating Character Replacement	Longest Repeating Character Replacement	O(n)	O(1)
124	Longest String Chain	Longest String Chain	O(n log n)	O(n)
125	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
126	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
127	Longest Word in Dictionary	Longest Word in Dictionary	O(n log n)	O(n)
128	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
129	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
130	Majority Element	Majority Element	O(n)	O(1)
131	Max Consecutive Ones III	Max Consecutive Ones III	O(n)	O(1)
132	Max Consecutive Ones III	Max Consecutive Ones III	O(n)	O(1)
133	Max Sum of Rectangle No Larger Than K	[Max Sum of Rectangle No Larger Than K	n log(n)	O(n)
134	Maximal Rectangle	Maximal Rectangle	O(n)	O(n)
135	Maximal Square	Maximal Square	O(n^2)	O(n^2)
136	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
137	Maximum Number of Balloons	here	O(n)	O(1)
138	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
139	Maximum Subarray	Maximum Subarray	O(n)	O(n)
140	Maximum Subarray	Maximum Subarray	O(n)	O(n)
141	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(log n)	O(1)
142	Meeting Rooms	Meeting Rooms	O(n log n)	O(n)
143	Meeting Rooms II	Meeting Rooms II	O(n log n)	O(n)
144	Merge Intervals	Merge Intervals	O(n log n)	O(n)
145	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
146	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
147	Merge Two Sorted Lists	Merge Two Sorted Lists	O(n)	O(n)
148	Min Stack	Min Stack	O(n)	O(n)
149	Minesweeper	Minesweeper	O(n^2)	O(1)
150	Minimum Area Rectangle	Minimum Area Rectangle	O(n^2)	O(n)
151	Minimum Difference Between Largest and Smallest Value in Three Moves	Minimum Difference Between Largest and Smallest Value in Three Moves	O(n log n)	O(n)
152	Minimum Domino Rotations For Equal Row	Minimum Domino Rotations For Equal Row	O(n)	O(1)
153	Minimum Knight Moves	Minimum Knight Moves	O(n)	O(n)
154	Minimum Number of Operations to Convert Time	Minimum Number of Operations to Convert Time	O(n)	O(1)
155	Minimum Obstacle Removal to Reach Corner	Minimum Obstacle Removal to Reach Corner	O(n^2)	O(n)
156	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
157	Minimum Remove to Make Valid Parentheses	Minimum Remove to Make Valid Parentheses	O(n)	O(n)
158	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
159	Mirror Reflection	Mirror Reflection	O(n^2)	O(1)
160	Missing Number	Missing Number	O(n)	O(1)
161	Move Zeroes	Move Zeroes	O(n)	O(1)
162	Multiply Strings	Multiply Strings	O(n^2)	O(n)
163	N-Queens	N-Queens	O(n!)	O(n!)
164	Network Delay Time	Network Delay Time	O(n log n)	O(n)
165	Next Greater Element II	Next Greater Element II	O(n)	O(n)
166	Next Permutation	Next Permutation	O(n)	O(1)
167	Non-overlapping Intervals	Non-overlapping intervals	O(n)	O(n)
168	Number of Boomerangs	Number of Boomerangs	O(n^2)	(O(n))
169	Number of Closed Islands	Number of Closed Islands	O(n^2)	O(n^2)
170	Number of Connected Components in an Undirected Graph	Number of Connected Components in an Undirected Graph	O(log n)	O(n)
171	Number of Enclaves	Number of Enclaves	O(n^2)	O(n^2)
172	Number of Good Ways to Split a String	Number of Good Ways to Split a String	O(n)	O(n)
173	Number of Islands	Number of Islands	O(n^2)	O(n^2)
174	Number of Provinces	Number of Provinces	O(n^2)	O(n)
175	Number of 1 Bits	Number of 1 bits	O(log n)	O(1)
176	Output Contest Matches	Output Contest Matches	O(log n)	O(n)
177	Palindrome Number	Palindrome Number	O(log n)	O(1)
178	Palindrome Permutation	Palindrome Permutation	O(n)	O(n)
179	Palindrome Permutation II	Palindrome Permutation II	O(n)	O(n)
180	Palindromic Substrings	Palindromic Substrings	O(n^2)	O(n^2)
181	Partition Equal Subset Sum	Partition Equal Subset Sum	O(n^2)	O(n)
182	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
183	Pascal's Triangle II	Pascal's Triangle II	O(n^2)	O(n^2)
184	Path with Maximum Gold	Path with Maximum Gold	O(2^n)	O(n)
185	Perfect Rectangle	Perfect Rectangle	O(n log n)	O(n)
186	Perfect Squares	Perfect Squares	O(n)	O(n)
187	Permutations	Permutations	O(n!)	O(n!)
188	Permutations II	Permutations II	O(n!)	O(n!)
189	Plus One	Plus One	O(n)	O(n)
190	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
191	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
192	Queue Reconstruction by Height	Queue Reconstruction by Height	O(n log n)	O(n)
193	Random Pick with Weight	Random Pick with Weight	O(log n)	O(n)
194	Rectangle Area	Rectangle Area	O(1)	O(1)
195	Regular Expression Matching	Regular Expression Matching	O(n^2)	O(n^2)
196	Remove All Adjacent Duplicates in String II)	Remove All Adjacent Duplicates in String II	O(n)	O(n)
197	Remove Duplicate Letters	Remove Duplicate Letters	O(n)	O(1)
198	Remove Duplicates from Sorted Array	Remove Duplicates from Sorted Array	O(n)	O(1)
199	Remove Element	Remove Element	O(n)	O(1)
200	Remove Invalid Parentheses	Remove Invalid Parentheses	O(2^n)	O(n)
201	Remove Nth Node From End of List	Remove Nth Node From End of List	O(n)	O(1)
202	Reorder List	Reorder List	O(n)	O(n)
203	Reverse Bits	Reverse bits	O(1)	O(1)
204	Reverse Integer	Reverse Integer	O(log(n)	O(1)
205	Reverse Linked List	Reverse Linked List	O(n)	O(n)
206	Reverse Nodes in k-Group	Reverse Nodes in k-Group
207	Reverse Words in a String	Reverse Words in a String	O(n)	O(1)
208	Reverse Words in a String III	Reverse Words in a String III	O(n)	O(n)
209	Roman to Integer	Roman to Integer	O(n)	O(1)
210	Rotate Array	Rotate Array	O(n)	O(1)
211	Rotate Image	Rotate Image	O(n^2)	O(1)
212	Same Tree	Same Tree	O(log n)	O(1)
213	Search a 2D Matrix	Search a 2D Matrix	O(log n)	O(1)
214	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
215	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
216	Search in Rotated Sorted Array II	Search in Rotated Sorted Array II	O(log n)	O(1)
217	Search Insert Position	Search Insert Position	O(log n)	O(1)
218	Serialize and Deserialize BST	Serialize and Deserialize BST	O(n)	O(n)
219	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
220	Shortest Bridge	Shortest Bridge	O(n^2)	O(n^2)
221	Shortest Palindrome	Shortest Palindrome	O(n^2)	O(n)
222	Shortest Word Distance	Shortest Word Distance	O(n)	O(1)
223	Simplify Path	Simplify Path	O(n)	O(n)
224	Single Number	Single Number	O(n)	O(1)
225	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
226	Solve the Equation	Solve the Equation	O(n)	O(1)
227	Sort Colors	Sort Colors	O(n)	O(1)
228	Sort Integers by The Power Value	Sort Integers by The Power Value	O(n log n)	O(n)
229	Sorting the Sentence	Sorting the Sentence	O(n log n)	O(n)
230	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
231	Spiral Matrix II	Spiral Matrix II	O(n^2)	O(n^2)
232	Split Array into Consecutive Subsequences	Split Array into Consecutive Subsequences	O(n)	O(n)
233	Split Array Largest Sum	Split Array Largest Sum	O(log n	O(1)
234	Sqrt(x)	Sqrt(x)	O(log n)	O(1)
235	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
236	Strobogrammatic Number	Strobogrammatic Number	O(n)	O(1)
237	Subarray Sum Equals K	Subarray Sum Equals K	O(n)	O(n)
238	Subsets	Subsets	O(2^n)	O(2^n)
239	Subtree of Another Tree	Subtree of Another Tree	O(n^2)	O(n)
240	Sudoku Solver	Sudoku Solver	O(2^n)	O(n^2))
241	Sum of Two Integers	Sum of Two Integers	O(1)	O(1)
242	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
243	Symmetric Tree	Symmetric Tree	O(n)	O(n)
244	Target Sum	Target Sum	O(2^n)	O(n)
245	Task Scheduler	Task Scheduler	O(n log n)	O(n)
246	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
247	Third Maximum Number	Third Maximum Number	O(n)	O(1)
248	Time Needed to Inform All Employees	Time Needed to Inform All Employees	O(n)	O(n)
249	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
250	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
251	Tree Diameter	Tree Diameter	O(n)	O(n)
252	Two Sum	Two Sum	O(n)	O(n)
253	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
254	Two Sum Less Than K	Two Sum Less Than K	O(n log n	O(1)
255	Unique Binary Search Trees	Unique Binary Search Trees	O(n^2)	O(n)
256	Unique Paths	Unique Paths	O(n^2)	O(n^2)
257	Unique Paths II	Unique Paths II	O(n^2)	O(n)
258	Valid Anagram	Valid Anagram	O(n)	O(n)
259	Valid Number	Valid Number	O(n)	O(1)
260	Valid Palindrome	Valid Palindrome	O(n)	O(n)
261	Valid Palindrome II	Valid Palindrome II	O(n)	O(1)
262	Valid Parentheses	Valid Parentheses	O(n)	O(n)
263	Valid Parenthesis String	Valid Parenthesis String	O(n)	O(1)
264	Valid Perfect Square	Valid Perfect Square	O(log n)	O(1)
265	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
266	Validate Binary Search Tree	Validate Binary Search Tree	O(n)	O(n)
267	Validate Stack Sequences	Validate Stack Sequences	O(n)	O(n)
268	Verifying an Alien Dictionary	Verifying an Alien Dictionary	O(n log n)	O(n)
269	Walls And Gates	Walls And Gates	O(n^2)	O(n^2)
270	Wildcard Matching	Wildvard Matching	O(n^2)	O(n^2)
271	Word Break	Word Break	O(n^2)	O(n)
272	Word Break II	Word Break II	O(n^2)	O(n)
273	Word Ladder	Word Ladder	O(n^2)	O(n^2)
274	Word Ladder II	Word Ladder II	O(n)	O(n)
275	Word Search	Word Search	O(n^2)	O(n)
276	Word Search II	Word Search II	O(n^2)	O(n^2)
277	X of a Kind in a Deck of Cards	X of a Kind in a Deck of Cards	O(n log n)	O(n)
278	ZigZag Conversion	ZigZag Conversion	O(n)	O(n)
279	Find Kth Largest XOR Coordinate Value	Find Kth Largest XOR Coordinate Value	O(n^2 + n log n)	O(n^2)
280	Maximum Number of Accepted Invitations	Maximum Number of Accepted Invitations	O(n^2)	O(n)
281	Arithmetic Subarrays	Arithmetic Subarrays	O(n log n)	O(n)
282	Find And Replace in String	Find And Replace in String	O(n + n log n)	O(n)
283	Special Array With X Elements Greater Than or Equal X	Special Array With X Elements Greater Than or Equal X	O(n^2)	O(1)
284	Peak Index in a Mountain Array	Peak Index in a Mountain Array	O(log n)	O(1)
285	Determine if Two Strings Are Close	Determine if Two Strings Are Close	O(n)	O(1)
286	Split a String Into the Max Number of Unique Substrings	Split a String Into the Max Number of Unique Substrings	O(2^n)	O(2^n)
287	Regions Cut By Slashes	Regions Cut By Slashes	O(n^2)	O(n^2)
288	Increment Submatrices by One	Increment Submatrices by One	O(n^2)	O(n^2)
289	Count Numbers with Unique Digits	Count Numbers with Unique Digits	O(n)	O(1)
290	Merge In Between Linked Lists	Merge In Between Linked Lists	O(n)	O(1)
291	Painting a Grid With Three Different Colors	Painting a Grid With Three Different Colors	O(R^2 * n)	O(R^2 + R * n)
292	Maximum Gap	Maximum Gap	O(n)	O(n)
293	Pizza with 3n Slices	Pizza with 3n Slices	O(n^2)	O(n^2)
294	Top K Frequent Elements	Top K Frequent Elements	O(n + m log m)	O(n)
295	Minimum Time Difference	Minimum Time Difference	O(n log n)	O(n)
296	Process Tasks Using Serverse	Process Tasks Using Servers	O(n log m)	O(m)
297	Arithmetic Slices	Arithmetic Slices	O(n)	O(n)

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Total Number

Total number of LeetCode solutions per comapny are shown below:^*

Company Name	Total Solutions
Google	194
Amazon	172
Apple	166
Meta	146
Adobe	133
Microsoft	130
Bloomberg	130
Uber	107
Goldman Sachs	105
TikTok	57
LinkedIn	45
Tesla	35
Airbnb	34
Twitter	32
Spotify	21
DE Shaw	17
Reddit	15
Netflix	7
Others	ALL

^* To be updaded as going through the list of Problems and Solutions section and updating weekly after the solution is added and visualising which companies have that problem. Currently details of the problems that belong to specific company are commented under the company name by inspecting README

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Must Do Problems

(Back to top)

No.	Question	Solution	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Merge Two Sorted Lists	Merge Two Sorted Lists	O(n)	O(n)
3	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
4	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
5	Reverse Bits	Reverse bits	O(1)	O(1)
6	Number of 1 Bits	Number of 1 bits	O(log n)	O(1)
7	Contains Duplicate	Contains Duplicate	O(n)	O(n)
8	Meeting Rooms	Meeting Rooms	O(n log n)	O(1)
9	Missing Number	Missing Number	O(n)	O(1)
10	Counting Bits	Counting bits	O(n log n)	O(n)
11	Merge Intervals	Merge Intervals	O(n log n)	O(n)
12	Insert Interval	Insert Interval	O(n)	O(n)
13	Valid Palindrome	Valid Palindrome	O(n)	O(n)
14	Valid Parentheses	Valid Parentheses	O(n)	O(n)
15	Climbing Stairs	Climbing Stairs	O(n)	O(n)
16	Same Tree	Same Tree	O(log n)	O(1)
17	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
18	Linked List Cycle	Linked List Cycle	O(n)	O(n)
19	Reverse Linked List	Reverse Linked List	O(n)	O(n)
20	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
21	Valid Anagram	Valid Anagram	O(n)	O(n)
22	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
23	Subtree of Another Tree	Subtree of Another Tree	O(n^2)	O(n)
24	Combination Sum	Combination Sum	O(2^n)	O(n)
25	Container With Most Water	Container With Most Water	O(n)	O(1)
26	3Sum	3Sum	O(n^2)	O(n)
27	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
28	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
29	Rotate Image	Rotate Image	O(n^2)	O(1)
30	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
31	Word Search	Word Search	O(n^2)	O(n)
32	Word Break	Word Break	O(n^2)	O(n)
33	Number of Islands	Number of Islands	O(n^2)	O(n^2)
34	Coin Change	Coin Change	O(n^2)	O(n)
35	Course Schedule	Course Schedule	O(n)	O(n)
36	Decode Ways	Decode Ways	O(n)	O(n)
37	House Robber	House Robber	O(n)	O(1)
38	Group Anagrams	Group Anagrams	O(n)	O(n)
39	Find the Duplicate Number	Find the Duplicate Number	O(n)	O(n)
40	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
41	Sum of Two Integers	Sum of Two Integers	O(1)	O(1)
42	Maximum Subarray	Maximum Subarray	O(n)	O(n)
43	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
44	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
45	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
46	Palindromic Substrings	Palindromic Substrings	O(n^2)	O(n^2)
47	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
48	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
49	Graph Valid Tree	Graph Valid Tree	O(n)	O(n)
50	Unique Paths	Unique Paths	O(n^2)	O(n^2)
51	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
52	Remove Nth Node From End of List	Remove Nth Node From End of List	O(n)	O(1)
53	Jump Game	Jump Game	O(n^2)	O(1)
54	Reorder List	Reorder List	O(n)	O(n)
55	Validate Binary Search Tree	Validate Binary Search Tree	O(n)	O(n)
56	Binary Tree Level Order Traversal	Binary Tree Level Order Traversal	O(n)	O(n)
57	Construct Binary Tree from Preorder and Inorder Traversal	Construct Binary Tree from Preorder and Inorder Traversal	O(n)	O(n)
58	Clone Graph	Clone Graph	O(n)	O(n)
59	Kth Smallest Element in a BST	Kth Smallest Element in a BST	O(n)	O(n)
60	Encode and Decode Strings	Encode and Decode Strings	O(n)	O(n)
61	Design Add and Search Words Data Structure	Design Add and Search Words Data Structure	O(n)	O(n)
62	Serialize and Deserialize BST	Serialize and Deserialize BST	O(n)	O(n)
63	Longest Common Subsequence	Longest Common Subsequence	O(n)	O(n)
64	Longest Increasing Subsequence	Longest Increasing Subsequence	O(n^2)	O(n)
65	Pacific Atlantic Water Flow	Pacific Atlantic Water Flow	O(n^2)	O(n^2)
66	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
67	Longest Repeating Character Replacement	Longest Repeating Character Replacement	O(n)	O(1)
68	Non-overlapping Intervals	Non-overlapping intervals	O(n)	O(n)
69	Number of Connected Components in an Undirected Graph	Number of Connected Components in an Undirected Graph	O(log n)	O(n)
70	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
71	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
72	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
73	House Robber II	House Robber II	O(n)	O(n)
74	Meeting Rooms II	Meeting Rooms II	O(n log n)	O(n)
75	Word Search II	Word Search II	O(n^2)	O(n^2)
76	Binary Tree Maximum Path Sum	Binary Tree Maximum Path Sum	O(n)	O(n)
77	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)

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Google Top

(Back to top)

No.	Question	Solutiion	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Maximal Rectangle	Maximal Rectangle	O(n)	O(n)
3	Insert Interval	Insert Interval	O(n)	O(n)
4	X of a Kind in a Deck of Cards	X of a Kind in a Deck of Cards	O(n log n)	O(n)
5	Maximal Square	Maximal Square	O(n^2)	O(n^2)
6	Bulls and Cows	Bulls and Cows	O(n)	O(1)
7	Evaluate Division	Evaluate Division	O(n^2)	O(n^2)
8	Decode String	Decode String	O(n)	O(n)
9	Longest String Chain	Longest String Chain	O(n log n)	O(n)
10	Validate Stack Sequences	Validate Stack Sequences	O(n)	O(n)
11	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
12	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
13	Longest Increasing Path in a Matrix	Longest Increasing Path in a Matrix	O(n^2)	O(n^2)
14	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
15	Count of Smaller Numbers After Self	Count of Smaller Numbers After Self	O(n log n)	O(n)
16	Network Delay Time	Network Delay Time	O(n log n)	O(n)
17	Subarray Sum Equals K	Subarray Sum Equals K	O(n)	O(n)
18	Max Sum of Rectangle No Larger Than K	Max Sum of Rectangle No Larger Than K	n log(n)	O(n)
19	Split Array into Consecutive Subsequences	Split Array into Consecutive Subsequences	O(n)	O(n)
20	Split Array Largest Sum	Split Array Largest Sum	O(log n	O(1)
21	Minimum Domino Rotations For Equal Row	Minimum Domino Rotations For Equal Row	O(n)	O(1)
22	Random Pick with Weight	Random Pick with Weight	O(log n)	O(n)

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License

LICENSE