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 or SQL solution to the problem found at LeetCode (primarily) or HackerRank is solved. The solutions to LeetCode problems are posted at the discussion sections in each solved problem 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 with Google Top, LinkedIn, Meta, Microsoft, Netflix, Reddit, Spotify, Tesla, TikTok, Twitter or Uber then that solution of specific company is added to the company's section as my GitHub solution found through contents. Otherwise it is added here as the solved problem is not glued to any of the high-tier companies' section; it is just a random problem that was solved.

The progress of my LeetCode account regarding these solutions with additional information on them can be found by looking at my LeetCode profile.

The Leetcode solutions of Python are found here while HackerRank solutions of Python 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 found through contents. By pressing on that company you will be redirected to the problem description (1^st column) followed by the solution implemented in PyCharm (2^nd column).

Currently, doing Python 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 high-tier company where it is a common interview question to be asked to solve. The problems for a particular company is seen through contents list.

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

Table of Contents

• Table of contents
• Preparation for Interiews
• Must Do Problems
• Adobe
• Airbnb
• Amazon
• Apple
• Bloomberg
• DE Shaw
• Goldman Sachs
• Google Top
• Google
• LinkedIn
• Meta
• Microsoft
• Netflix
• Reddit
• Spotify
• Tesla
• TikTok
• Twitter
• Uber
• Others

Preparation for Interviews

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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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Must Do Problems

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No.	Questions	Solution in PyCharm	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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Adobe

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Mirror Reflection	Mirror Reflection	O(n^2)	O(1)
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	Number of 1 Bits	Number of 1 bits	O(log n)	O(1)
6	Contains Duplicate	Contains Duplicate	O(n)	O(n)
7	Missing Number	Missing Number	O(n)	O(1)
8	Counting Bits	Counting bits	O(n log n)	O(n)
9	Merge Intervals	Merge Intervals	O(n log n)	O(n)
10	Valid Palindrome	Valid Palindrome	O(n)	O(n)
11	Valid Parentheses	Valid Parentheses	O(n)	O(n)
12	Climbing Stairs	Climbing Stairs	O(n)	O(n)
13	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
14	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
15	Container With Most Water	Container With Most Water	O(n)	O(1)
16	3Sum	3Sum	O(n^2)	O(n)
17	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
18	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
19	Rotate Image	Rotate Image	O(n^2)	O(1)
20	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
21	Word Break	Word Break	O(n^2)	O(n)
22	Number of Islands	Number of Islands	O(n^2)	O(n^2)
23	Coin Change	Coin Change	O(n^2)	O(n)
24	Maximum Subarray	Maximum Subarray	O(n)	O(n)
25	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
26	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
27	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
28	Valid Anagram	Valid Anagram	O(n)	O(n)
29	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
30	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
31	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
32	Maximal Square	Maximal Square	O(n^2)	O(n^2)
33	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
34	Word Search	Word Search	O(n^2)	O(n)
35	Word Search II	Word Search II	O(n^2)	O(n^2)
36	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
37	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
38	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
39	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
40	Min Stack	Min Stack	O(n)	O(n)
41	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
42	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
43	Linked List Cycle	Linked List Cycle	O(n)	O(n)
44	Clone Graph	Clone Graph	O(n)	O(n)
45	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
46	Word Ladder	Word Ladder	O(n^2)	O(n^2)
47	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
48	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
49	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
50	Reverse Linked List	Reverse Linked List	O(n)	O(n)
51	Count Primes	Count Primes	O(n log n)	O(n log n)
52	House Robber	House Robber	O(n)	O(1)
53	Decode Ways	Decode Ways	O(n)	O(n)
54	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
55	Subsets	Subsets	O(2^n)	O(2^n)
56	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
57	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
58	Unique Paths	Unique Paths	O(n^2)	O(n^2)
59	Jump Game	Jump Game	O(n^2)	O(1)
60	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
61	N-Queens	N-Queens	O(n!)	O(n!)
62	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
63	Group Anagrams	Group Anagrams	O(n)	O(n)
64	Permutations	Permutations	O(n!)	O(n!)
65	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
66	Combination Sum	Combination Sum	O(2^n)	O(n)
67	Count and Say	Count and say	O(2^n)	O(n)
68	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
69	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
70	Next Permutation	Next Permutation	O(n)	O(1)
71	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
72	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
73	3Sum Closest	3Sum Closest	O(n^2)	O(1)
74	Roman to Integer	Roman to Integer	O(n)	O(1)
75	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
76	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
77	Add Two Numbers	Add Two Numbers	O(n)	O(n)
78	Two Sum	Two Sum	O(n)	O(n)
79	Daily Temperatures	Daily Temperatures
80	Basic Calculator	Basic Calculator
81	Basic Calculator II	Basic Calculator II
82	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
83	Game of Life	Game of Life
84	Regular Expression Matching	Regular Expression Matching
85	Wildcard Matching	Wildvard Matching
86	Single Number	Single Number
87	Happy Number	Happy Number
88	Contains Duplicate II	Contains Duplicate II
89	Contains Duplicate III	Contains Duplicate III
90	Add Strings	Add Strings
99	Reverse Nodes in k-Group	Reverse Nodes in k-Group
100	Sudoku Solver	Sudoku Solver
101	Multiply Strings	Multiply Strings
102	Sort Colors	Sort Colors
103	Course Schedule	Course Schedule	O(n)	O(n)
104	Move Zeroes	Move Zeroes
105	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
106	Subarray Sum Equals K	Subarray Sum Equals K
107	Maximum Number of Balloons	here
108	Jump Game II	Jump Gmae II.
109	Find All Duplicates in an Array	Find All Duplicates in an Array
110	Reverse Words in a String	Reverse Words in a String
111	Word Pattern	Word Pattern
112	Search a 2D Matrix	Search a 2D Matrix
113	Longest Word in Dictionary	Longest Word in Dictionary
114	Largest Number	Largest Number
115	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
116	Guess Number Higher or Lower	Guess Number Higher or Lower
117	Island Perimeter	Island Perimeter
118	Flood fill	Flood fill
119	Find if Path Exists in Graph	Find if Path Exists in Graph
120	Symmetric Tree	Symmetric Tree	O(n)	O(n)
121	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
122	4Sum	4Sum	O(n^2)	O(n)
123	Binary Search	Binary Search	O(log n)	O(1)

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Airbnb

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Combination Sum	Combination Sum	O(2^n)	O(n)
3	Combination Sum II	Combination Sum II
4	Contains Duplicate	Contains Duplicate	O(n)	O(n)
5	Contains Duplicate II	Contains Duplicate II
6	Contains Duplicate III	Contains Duplicate III
7	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
8	Maximal Square	Maximal Square	O(n^2)	O(n^2)
9	Word Search II	Word Search II	O(n^2)	O(n^2)
10	Fraction to Recurring Decimal	Fraction to Recurring Decimal
11	House Robber	House Robber	O(n)	O(1)
12	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
13	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
14	Add Two Numbers	Add Two Numbers	O(n)	O(n)
15	Median of Two Sorted Arrays	Median of Two Sorted Arrays
16	Regular Expression Matching	Regular Expression Matching
17	Valid Parentheses	Valid Parentheses	O(n)	O(n)
18	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
19	Wildcard Matching	Wildvard Matching
20	Single Number	Single Number
21	Fraction to Recurring Decimal	Fraction to Recurring Decimal
22	Reverse Bits	Reverse bits	O(1)	O(1)
23	Happy Number	Happy Number
24	Basic Calculator II	Basic Calculator II
25	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
26	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
27	Coin Change	Coin Change	O(n^2)	O(n)
28	Add Strings	Add Strings
29	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)

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Amazon

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Add Two Numbers	Add Two Numbers	O(n)	O(n)
3	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
4	Merge Two Sorted Lists	Merge Two Sorted Lists	O(n)	O(n)
5	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
6	Permutations	Permutations	O(n!)	O(n!)
7	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
8	Merge Intervals	Merge Intervals	O(n log n)	O(n)
9	Pascal's Triangle II	Pascal's Triangle II	O(n^2)	O(n^2)
10	Valid Parentheses	Valid Parentheses	O(n)	O(n)
11	Same Tree	Same Tree	O(log n)	O(1)
12	Linked List Cycle	Linked List Cycle	O(n)	O(n)
13	Reverse Linked List	Reverse Linked List	O(n)	O(n)
14	Valid Anagram	Valid Anagram	O(n)	O(n)
15	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
16	Subtree of Another Tree	Subtree of Another Tree	O(n^2)	O(n)
17	3Sum	3Sum	O(n^2)	O(n)
18	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
19	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
20	Rotate Image	Rotate Image	O(n^2)	O(1)
21	Word Break	Word Break	O(n^2)	O(n)
22	Number of Islands	Number of Islands	O(n^2)	O(n^2)
23	Group Anagrams	Group Anagrams	O(n)	O(n)
24	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
25	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
26	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
27	Validate Binary Search Tree	Validate Binary Search Tree	O(n)	O(n)
28	Binary Tree Level Order Traversal	Binary Tree Level Order Traversal	O(n)	O(n)
29	Serialize and Deserialize BST	Serialize and Deserialize BST	O(n)	O(n)
30	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
31	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
32	Word Search II	Word Search II	O(n^2)	O(n^2)
33	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
34	Subarray Sum Equals K	Subarray Sum Equals K
35	ZigZag Conversion	ZigZag Conversion
36	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
37	Find All Anagrams in a String	Find All Anagrams in a String
38	Basic Calculator	Basic Calculator
39	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
40	Sort Colors	Sort Colors
41	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
42	Word Ladder	Word Ladder	O(n^2)	O(n^2)
43	Edit Distance	Edit Distance
44	Rotate Array	Rotate Array
45	Count Primes	Count Primes	O(n log n)	O(n log n)
46	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
47	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
48	K Closest Points to Origin	K Closest Points to Origin
49	Subsets	Subsets	O(2^n)	O(2^n)
50	Happy Number	Happy Number
51	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
52	Min Stack	Min Stack	O(n)	O(n)
53	Spiral Matrix II	Spiral Matrix II
54	Unique Paths II	Unique Paths II
55	Accounts Merge	Accounts Merge
56	Gray Code	Gray Code
57	Word Ladder II	Word Ladder II
58	Third Maximum Number	Third Maximum Number
59	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
60	Median of Two Sorted Arrays	Median of Two Sorted Arrays
61	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
62	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
63	Minesweeper	Minesweeper
64	First Unique Character in a String	First Unique Character in a String
65	Find Pivot Index	Find Pivot Index
66	Solve the Equation	Solve the Equation
67	Combination Sum	Combination Sum	O(2^n)	O(n)
68	Combination Sum II	Combination Sum II
69	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
70	Container With Most Water	Container With Most Water	O(n)	O(1)
71	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
72	Word Search	Word Search	O(n^2)	O(n)
73	Coin Change	Coin Change	O(n^2)	O(n)
74	Maximum Subarray	Maximum Subarray	O(n)	O(n)
75	Remove All Adjacent Duplicates in String II)	Remove All Adjacent Duplicates in String II
76	High Five	High Five
77	Shortest Word Distance	Shortest Word Distance
78	Maximal Square	Maximal Square	O(n^2)	O(n^2)
79	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
80	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
81	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
82	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
83	Fraction to Recurring Decimal	Fraction to Recurring Decimal
84	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
85	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
86	Clone Graph	Clone Graph	O(n)	O(n)
87	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
88	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
89	Valid Palindrome	Valid Palindrome	O(n)	O(n)
90	House Robber	House Robber	O(n)	O(1)
91	Decode Ways	Decode Ways	O(n)	O(n)
92	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
93	Climbing Stairs	Climbing Stairs	O(n)	O(n)
94	Unique Paths	Unique Paths	O(n^2)	O(n^2)
95	Insert Interval	Insert Interval	O(n)	O(n)
96	Jump Game	Jump Game	O(n^2)	O(1)
97	N-Queens	N-Queens	O(n!)	O(n!)
98	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
99	Count and Say	Count and say	O(2^n)	O(n)
100	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
101	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
102	Next Permutation	Next Permutation	O(n)	O(1)
103	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
104	3Sum Closest	3Sum Closest	O(n^2)	O(1)
105	Roman to Integer	Roman to Integer	O(n)	O(1)
106	Daily Temperatures	Daily Temperatures
107	Game of Life	Game of Life
108	Regular Expression Matching	Regular Expression Matching
109	Wildcard Matching	Wildvard Matching
110	Single Number	Single Number
111	Reverse Bits	Reverse bits	O(1)	O(1)
112	Contains Duplicate II	Contains Duplicate II
113	Contains Duplicate III	Contains Duplicate III
114	Basic Calculator II	Basic Calculator II
115	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
116	Add Strings	Add Strings
117	Reverse Nodes in k-Group	Reverse Nodes in k-Group
118	Sudoku Solver	Sudoku Solver
119	Multiply Strings	Multiply Strings
120	Course Schedule	Course Schedule	O(n)	O(n)
121	Move Zeroes	Move Zeroes
122	Jump Game II	Jump Gmae II.
123	Course Schedule III	Course Schedule III
124	Find All Duplicates in an Array	Find All Duplicates in an Array
125	Excel Sheet Column Title	Excel Sheet Column Title
126	Reverse Words in a String	Reverse Words in a String
127	Word Pattern	Word Pattern
128	Search a 2D Matrix	Search a 2D Matrix
129	Longest Word in Dictionary	Longest Word in Dictionary
130	Largest Number	Largest Number
131	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
132	Guess Number Higher or Lower	Guess Number Higher or Lower
133	Number of Enclaves	Number of Enclaves
134	Walls And Gates	Walls And Gates
135	Island Perimeter	Island Perimeter
136	Flood fill	Flood fill
137	Find if Path Exists in Graph	Find if Path Exists in Graph
138	Symmetric Tree	Symmetric Tree	O(n)	O(n)
139	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
140	Number of Islands	Number of Islands	O(n^2)	O(n^2)
141	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
142	Jump Game III	Jump Game III	O(n)	O(n)
143	Kill process	Kill process	O(n)	O(n)
144	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
145	Brace Expansion	Brace Expansion	O(2^n)	O(2^n)
146	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
147	4Sum	4Sum	O(n^2)	O(n)
148	Binary Search	Binary Search	O(log n)	O(1)
149	Destination City	Destination City	O(n)	O(n)

---

Apple

(Back to top)

No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
3	3Sum	3Sum	O(n^2)	O(n)
4	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
5	Maximum Subarray	Maximum Subarray	O(n)	O(n)
6	Add Two Numbers	Add Two Numbers	O(n)	O(n)
7	Number of Islands	Number of Islands	O(n^2)	O(n^2)
8	Move Zeroes	Move Zeroes
9	Valid Parentheses	Valid Parentheses	O(n)	O(n)
10	Merge Intervals	Merge Intervals	O(n log n)	O(n)
11	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
12	Decode String	Decode String
13	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
14	Container With Most Water	Container With Most Water	O(n)	O(1)
15	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
16	Combination Sum	Combination Sum	O(2^n)	O(n)
17	Rotate Image	Rotate Image	O(n^2)	O(1)
18	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
19	Unique Paths	Unique Paths	O(n^2)	O(n^2)
20	Word Break	Word Break	O(n^2)	O(n)
21	Random Pick with Weight	Random Pick with Weight
22	Roman to Integer	Roman to Integer	O(n)	O(1)
23	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
24	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
25	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
26	Valid Palindrome	Valid Palindrome	O(n)	O(n)
27	House Robber	House Robber	O(n)	O(1)
28	First Bad Version	First Bad Version
29	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
30	Regular Expression Matching	Regular Expression Matching
31	Merge Two Sorted Lists	Merge Two Sorted Lists	O(n)	O(n)
32	Remove Duplicates from Sorted Array	Remove Duplicates from Sorted Array
33	Group Anagrams	Group Anagrams	O(n)	O(n)
34	Word Search	Word Search	O(n^2)	O(n)
35	Word Search II	Word Search II	O(n^2)	O(n^2)
36	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
37	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
38	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
39	Count of Smaller Numbers After Self	Count of Smaller Numbers After Self
40	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
41	Permutations	Permutations	O(n!)	O(n!)
42	Climbing Stairs	Climbing Stairs	O(n)	O(n)
43	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
44	Maximal Rectangle	Maximal Rectangle	O(n)	O(n)
45	Binary Tree Level Order Traversal	Binary Tree Level Order Traversal	O(n)	O(n)
46	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
47	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
48	Course Schedule	Course Schedule	O(n)	O(n)
49	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
50	Contains Duplicate	Contains Duplicate	O(n)	O(n)
51	Maximal Square	Maximal Square	O(n^2)	O(n^2)
52	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
53	H-Index	H-Index
54	Sort Colors	Sort Colors
55	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
56	Word Ladder	Word Ladder	O(n^2)	O(n^2)
57	Rotate Array	Rotate Array
58	Remove Duplicate Letters	Remove Duplicate Letters
59	3Sum Closest	3Sum Closest	O(n^2)	O(1)
60	Valid Parenthesis String	Valid Parenthesis String
61	Count Primes	Count Primes	O(n log n)	O(n log n)
62	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
63	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
64	Reverse Integer	Reverse Integer
65	Multiply Strings	Multiply Strings
66	Integer to Roman	Integer to Roman
67	First Missing Positive	First Missing Positive
68	Palindrome Number	Palindrome Number
69	N-Queens	N-Queens	O(n!)	O(n!)
70	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
71	Largest Rectangle in Histogram	Largest Rectangle in Histogram
72	Word Break II	Word Break II
73	Max Consecutive Ones III	Max Consecutive Ones III
74	Next Greater Element II	Next Greater Element II
75	Find First and Last Position of Element in Sorted Array	Find First and Last Position of Element in Sorted Array
76	Sqrt(x)	Sqrt(x)
77	Integer to English Words	Integer to English Words
78	Majority Element	Majority Element
79	Basic Calculator II	Basic Calculator II
80	Reverse Words in a String III	Reverse Words in a String III
122	4Sum	4Sum	O(n^2)	O(n)
82	Frog Jump	Frog Jumo
83	Happy Number	Happy Number
84	Sudoku Solver	Sudoku Solver
85	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
86	Min Stack	Min Stack	O(n)	O(n)
87	Median of Two Sorted Arrays	Median of Two Sorted Arrays
88	Valid Anagram	Valid Anagram	O(n)	O(n)
89	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
90	Coin Change	Coin Change	O(n^2)	O(n)
91	Remove All Adjacent Duplicates in String II)	Remove All Adjacent Duplicates in String II
92	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
93	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
94	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
95	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
96	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
97	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
98	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
99	Fraction to Recurring Decimal	Fraction to Recurring Decimal
100	Linked List Cycle	Linked List Cycle	O(n)	O(n)
101	Clone Graph	Clone Graph	O(n)	O(n)
102	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
103	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
104	Reverse Linked List	Reverse Linked List	O(n)	O(n)
105	Decode Ways	Decode Ways	O(n)	O(n)
106	Subsets	Subsets	O(2^n)	O(2^n)
107	Unique Paths II	Unique Paths II
108	Insert Interval	Insert Interval	O(n)	O(n)
109	Jump Game	Jump Game	O(n^2)	O(1)
110	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
111	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
112	Count and Say	Count and say	O(2^n)	O(n)
113	Next Permutation	Next Permutation	O(n)	O(1)
114	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
115	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
116	Daily Temperatures	Daily Temperatures
117	Basic Calculator	Basic Calculator
118	Basic Calculator II	Basic Calculator II
119	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
120	Game of Life	Game of Life
121	Wildcard Matching	Wildvard Matching
122	Single Number	Single Number
123	Reverse Bits	Reverse bits	O(1)	O(1)
124	Contains Duplicate III	Contains Duplicate III
125	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
126	Add Strings	Add Strings
127	Reverse Nodes in k-Group	Reverse Nodes in k-Group
128	Subarray Sum Equals K	Subarray Sum Equals K
129	Jump Game II	Jump Gmae II.
130	Find All Duplicates in an Array	Find All Duplicates in an Array
131	Reverse Words in a String	Reverse Words in a String
132	Word Pattern	Word Pattern
133	Search a 2D Matrix	Search a 2D Matrix
134	Check If N and Its Double Exist	Check If N and Its Double Exist	O(n)	O(n)
135	Largest Number	Largest Number
136	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
137	Guess Number Higher or Lower	Guess Number Higher or Lower
138	Walls And Gates	Walls And Gates
139	Island Perimeter	Island Perimeter
140	Flood fill	Flood fill
141	Find if Path Exists in Graph	Find if Path Exists in Graph
142	Symmetric Tree	Symmetric Tree	O(n)	O(n)
143	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
144	Number of Islands	Number of Islands	O(n^2)	O(n^2)
145	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
146	Jump Game III	Jump Game III	O(n)	O(n)
147	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
148	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
149	Binary Search	Binary Search	O(log n)	O(1)

---

Bloomberg

(Back to top)

No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Mirror Reflection	Mirror Reflection	O(n^2)	O(1)
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	Number of 1 Bits	Number of 1 bits	O(log n)	O(1)
6	Contains Duplicate	Contains Duplicate	O(n)	O(n)
7	Meeting Rooms	Meeting Rooms	O(n log n)	O(1)
8	Missing Number	Missing Number	O(n)	O(1)
9	Merge Intervals	Merge Intervals	O(n log n)	O(n)
10	Valid Palindrome	Valid Palindrome	O(n)	O(n)
11	Valid Parentheses	Valid Parentheses
12	Climbing Stairs	Climbing Stairs	O(n)	O(n)
13	Valid Anagram	Valid Anagram	O(n)	O(n)
14	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
15	Container With Most Water	Container With Most Water	O(n)	O(1)
16	3Sum	3Sum	O(n^2)	O(n)
17	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
18	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
19	Rotate Image	Rotate Image	O(n^2)	O(1)
20	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
21	Word Search	Word Search	O(n^2)	O(n)
22	Word Search II	Word Search II	O(n^2)	O(n^2)
23	Word Break	Word Break	O(n^2)	O(n)
24	Number of Islands	Number of Islands	O(n^2)	O(n^2)
25	Coin Change	Coin Change	O(n^2)	O(n)
26	Maximum Subarray	Maximum Subarray	O(n)	O(n)
27	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
28	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
29	Remove All Adjacent Duplicates in String II)	Remove All Adjacent Duplicates in String II
30	Palindrome Permutation	Palindrome Permutation
31	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
32	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
33	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
34	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
35	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
36	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
37	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
38	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
39	Two Sum	Two Sum	O(n)	O(n)
40	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
41	Min Stack	Min Stack	O(n)	O(n)
42	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
43	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
44	Linked List Cycle	Linked List Cycle	O(n)	O(n)
45	Clone Graph	Clone Graph	O(n)	O(n)
46	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
47	Word Ladder	Word Ladder	O(n^2)	O(n^2)
48	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
49	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
50	Reverse Linked List	Reverse Linked List	O(n)	O(n)
51	House Robber	House Robber	O(n)	O(1)
52	Decode Ways	Decode Ways	O(n)	O(n)
53	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
54	Subsets	Subsets	O(2^n)	O(2^n)
55	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
56	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
57	Unique Paths	Unique Paths	O(n^2)	O(n^2)
58	Unique Paths II	Unique Paths II
59	Insert Interval	Insert Interval
60	Jump Game	Jump Game	O(n^2)	O(1)
61	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
62	N-Queens	N-Queens	O(n!)	O(n!)
63	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
64	Group Anagrams	Group Anagrams	O(n)	O(n)
65	Permutations	Permutations	O(n!)	O(n!)
66	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
67	Combination Sum	Combination Sum	O(2^n)	O(n)
68	Count and Say	Count and say	O(2^n)	O(n)
69	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
70	Next Permutation	Next Permutation	O(n)	O(1)
71	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
72	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
73	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
74	3Sum Closest	3Sum Closest	O(n^2)	O(1)
75	Roman to Integer	Roman to Integer	O(n)	O(1)
76	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
77	Add Two Numbers	Add Two Numbers	O(n)	O(n)
78	Daily Temperatures	Daily Temperatures
79	Game of Life	Game of Life
80	Regular Expression Matching	Regular Expression Matching
81	Wildcard Matching	Wildvard Matching
82	Single Number	Single Number
83	Reverse Bits	Reverse bits	O(1)	O(1)
84	Happy Number	Happy Number
85	Contains Duplicate II	Contains Duplicate II
86	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
87	Add Strings	Add Strings
88	Reverse Nodes in k-Group	Reverse Nodes in k-Group
89	Sudoku Solver	Sudoku Solver
90	Multiply Strings	Multiply Strings
91	Sort Colors	Sort Colors
92	Course Schedule	Course Schedule	O(n)	O(n)
93	Move Zeroes	Move Zeroes
94	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
95	Subarray Sum Equals K	Subarray Sum Equals K
96	Jump Game II	Jump Gmae II.
97	Course Schedule III	Course Schedule III
98	Find All Duplicates in an Array	Find All Duplicates in an Array
99	Reverse Words in a String	Reverse Words in a String
100	Search a 2D Matrix	Search a 2D Matrix
101	Largest Number	Largest Number
102	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
103	Guess Number Higher or Lower	Guess Number Higher or Lower
104	Walls And Gates	Walls And Gates
105	Island Perimeter	Island Perimeter
106	Flood fill	Flood fill
107	Symmetric Tree	Symmetric Tree	O(n)	O(n)
108	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
109	Number of Islands	Number of Islands	O(n^2)	O(n^2)
110	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
111	Kill process	Kill process	O(n)	O(n)
112	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
113	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
114	4Sum	4Sum	O(n^2)	O(n)
115	Binary Search	Binary Search	O(log n)	O(1)

---

DE Shaw

(Back to top)

No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Maximum Subarray	Maximum Subarray	O(n)	O(n)
2	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
3	Daily Temperatures	Daily Temperatures
4	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
5	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
6	Max Consecutive Ones III	Max Consecutive Ones III
7	Verifying an Alien Dictionary	Verifying an Alien Dictionary	O(n log n)	O(n)
8	Longest Increasing Path in a Matrix	Longest Increasing Path in a Matrix
9	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
10	Number of Islands	Number of Islands	O(n^2)	O(n^2)
11	Group Anagrams	Group Anagrams	O(n)	O(n)
12	Rotate Image	Rotate Image	O(n^2)	O(1)
13	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
14	First Missing Positive	First Missing Positive
15	Next Permutation	Next Permutation	O(n)	O(1)
16	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
17	Container With Most Water	Container With Most Water	O(n)	O(1)

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Goldman Sachs

(Back to top)

No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
3	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
4	Counting Bits	Counting bits	O(n log n)	O(n)
5	Valid Parentheses	Valid Parentheses	O(n)	O(n)
6	Valid Anagram	Valid Anagram	O(n)	O(n)
7	3Sum	3Sum	O(n^2)	O(n)
8	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
9	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
10	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
11	Remove All Adjacent Duplicates in String II)	Remove All Adjacent Duplicates in String II
12	Maximum Subarray	Maximum Subarray	O(n)	O(n)
13	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
14	Daily Temperatures	Daily Temperatures
15	Number of Islands	Number of Islands	O(n^2)	O(n^2)
16	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
17	Group Anagrams	Group Anagrams	O(n)	O(n)
18	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
19	Next Permutation	Next Permutation	O(n)	O(1)
20	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
21	Container With Most Water	Container With Most Water	O(n)	O(1)
22	High Five	High Five
23	Palindrome Permutation	Palindrome Permutation
24	Find Pivot Index	Find Pivot Index
25	Palindromic Substrings	Palindromic Substrings	O(n^2)	O(n^2)
26	Find All Anagrams in a String	Find All Anagrams in a String
27	Pacific Atlantic Water Flow	Pacific Atlantic Water Flow	O(n^2)	O(n^2)
28	Evaluate Division	Evaluate Division
29	Decode String	Decode String
30	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
31	Counting Bits	Counting bits	O(n log n)	O(n)
32	Coin Change	Coin Change	O(n^2)	O(n)
33	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
34	Find the Duplicate Number	Find the Duplicate Number	O(n)	O(n)
35	Move Zeroes	Move Zeroes
36	First Bad Version	First Bad Version
37	H-Index	H-Index
38	Meeting Rooms II	Meeting Rooms II	O(n log n)	O(n)
39	Shortest Word Distance	Shortest Word Distance
40	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
41	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
42	Maximal Square	Maximal Square	O(n^2)	O(n^2)
43	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
44	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
45	Word Search	Word Search	O(n^2)	O(n)
46	Word Search II	Word Search II	O(n^2)	O(n^2)
47	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
48	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
49	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
50	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
51	Fraction to Recurring Decimal	Fraction to Recurring Decimal
52	Min Stack	Min Stack	O(n)	O(n)
53	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
54	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
55	Linked List Cycle	Linked List Cycle	O(n)	O(n)
56	Word Break	Word Break	O(n^2)	O(n)
57	Clone Graph	Clone Graph	O(n)	O(n)
58	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
59	Word Ladder	Word Ladder	O(n^2)	O(n^2)
60	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
61	Pascal's Triangle II	Pascal's Triangle II	O(n^2)	O(n^2)
62	Valid Palindrome	Valid Palindrome	O(n)	O(n)
63	Reverse Linked List	Reverse Linked List	O(n)	O(n)
64	Count Primes	Count Primes	O(n log n)	O(n log n)
65	House Robber	House Robber	O(n)	O(1)
66	Decode Ways	Decode Ways	O(n)	O(n)
67	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
68	Subsets	Subsets	O(2^n)	O(2^n)
69	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
70	Climbing Stairs	Climbing Stairs	O(n)	O(n)
71	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
72	Unique Paths	Unique Paths	O(n^2)	O(n^2)
73	Unique Paths II	Unique Paths II
74	Insert Interval	Insert Interval	O(n)	O(n)
75	Merge Intervals	Merge Intervals	O(n log n)	O(n)
76	Jump Game	Jump Game	O(n^2)	O(1)
77	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
78	N-Queens	N-Queens	O(n!)	O(n!)
79	Group Anagrams	Group Anagrams	O(n)	O(n)
80	Permutations	Permutations	O(n!)	O(n!)
81	Combination Sum	Combination Sum	O(2^n)	O(n)
82	Count and Say	Count and say	O(2^n)	O(n)
83	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
84	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
85	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
86	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
87	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
88	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
89	3Sum Closest	3Sum Closest	O(n^2)	O(1)
90	Roman to Integer	Roman to Integer	O(n)	O(1)
91	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
92	Add Two Numbers	Add Two Numbers	O(n)	O(n)
93	Jump Game II	Jump Gmae II.
94	Search a 2D Matrix	Search a 2D Matrix
95	Longest Word in Dictionary	Longest Word in Dictionary
96	Determine if Two Events Have Conflict	Determine if Two Events Have Conflict
97	Largest Number	Largest Number
98	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
99	Symmetric Tree	Symmetric Tree	O(n)	O(n)
100	Number of Islands	Number of Islands	O(n^2)	O(n^2)
101	Jump Game III	Jump Game III	O(n)	O(n)
102	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
103	Binary Search	Binary Search	O(log n)	O(1)

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No.	Questions	Solution in PyCharm	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
8	Decode String	Decode String
9	Longest String Chain	Longest String Chain
10	Validate Stack Sequences	Validate Stack Sequences
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
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
16	Network Delay Time	Network Delay Time
17	Subarray Sum Equals K	Subarray Sum Equals K
18	Max Sum of Rectangle No Larger Than K	[Max Sum of Rectangle No Larger Than K
19	Split Array into Consecutive Subsequences	Split Array into Consecutive Subsequences
20	Split Array Largest Sum	Split Array Largest Sum
21	Minimum Domino Rotations For Equal Row	Minimum Domino Rotations For Equal Row
22	Random Pick with Weight	Random Pick with Weight

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
3	Remove Duplicates from Sorted Array	Remove Duplicates from Sorted Array
4	Next Permutation	Next Permutation	O(n)	O(1)
5	Maximal Rectangle	Maximal Rectangle	O(n)	O(n)
6	Move Zeroes	Move Zeroes
7	Merge Intervals	Merge Intervals	O(n log n)	O(n)
8	Insert Interval	Insert Interval	O(n)	O(n)
9	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
10	Valid Parentheses	Valid Parentheses	O(n)	O(n)
11	Same Tree	Same Tree	O(log n)	O(1)
12	Plus One	Plus One
13	Bulls and Cows	Bulls and Cows	O(n)	O(1)
14	Evaluate Division	Evaluate Division
15	Decode String	Decode String
16	Word Break	Word Break	O(n^2)	O(n)
17	Number of Islands	Number of Islands	O(n^2)	O(n^2)
18	House Robber	House Robber	O(n)	O(1)
19	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
20	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
21	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
22	Clone Graph	Clone Graph	O(n)	O(n)
23	Kth Smallest Element in a BST	Kth Smallest Element in a BST	O(n)	O(n)
24	Longest Increasing Subsequence	Longest Increasing Subsequence	O(n^2)	O(n)
25	Pacific Atlantic Water Flow	Pacific Atlantic Water Flow	O(n^2)	O(n^2)
26	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
27	Word Search II	Word Search II	O(n^2)	O(n^2)
28	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
29	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
30	Longest Increasing Path in a Matrix	Longest Increasing Path in a Matrix
31	Find Median from Data Stream	Find Median from Data Stream	O(log n)	O(n)
32	Count of Smaller Numbers After Self	Count of Smaller Numbers After Self
33	Subarray Sum Equals K	Subarray Sum Equals K
34	Max Sum of Rectangle No Larger Than K	[Max Sum of Rectangle No Larger Than K
35	Split Array into Consecutive Subsequences	Split Array into Consecutive Subsequences
36	Split Array Largest Sum	Split Array Largest Sum
37	Target Sum	Target Sum
38	H-Index	H-Index
39	Regular Expression Matching	Regular Expression Matching
40	Basic Calculator	Basic Calculator
41	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
42	Wildcard Matching	Wildvard Matching
43	Add Strings	Add Strings
44	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
45	Word Ladder	Word Ladder	O(n^2)	O(n^2)
46	Shortest Palindrome	Shortest Palindrome
47	Remove Duplicate Letters	Remove Duplicate Letters
48	Valid Parenthesis String	Valid Parenthesis String
49	Game of Life	Game of Life
50	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
51	Word Break II	Word Break II
52	Next Greater Element II	Next Greater Element II
53	K Closest Points to Origin	K Closest Points to Origin
54	Expression Add Operators	Expression Add Operators
55	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
56	Combination Sum IV	Combination Sum IV
57	Min Stack	Min Stack	O(n)	O(n)
58	Fraction to Recurring Decimal	Fraction to Recurring Decimal
59	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
60	Perfect Squares	Perfect Squares
61	Find the Difference	Find the Difference
62	Daily Temperatures	Daily Temperatures
63	Isomorphic Strings	Isomorphic Strings
64	Max Consecutive Ones	Max Concsecutive Ones
65	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
66	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
67	First Unique Character in a String	First Unique Character in a String
68	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
69	Valid Anagram	Valid Anagram	O(n)	O(n)
70	Container With Most Water	Container With Most Water	O(n)	O(1)
71	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
72	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
73	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
74	Word Search	Word Search	O(n^2)	O(n)
75	Coin Change	Coin Change	O(n^2)	O(n)
76	Maximum Subarray	Maximum Subarray	O(n)	O(n)
77	Palindrome Permutation	Palindrome Permutation
78	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
79	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
80	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
81	Best Time to Buy and Sell Stock II	Best Time to Buy and Sell Stock II	O(n)	O(1)
82	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
83	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
84	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
85	Linked List Cycle	Linked List Cycle	O(n)	O(n)
86	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
87	Valid Palindrome	Valid Palindrome	O(n)	O(n)
88	Reverse Linked List	Reverse Linked List	O(n)	O(n)
89	Decode Ways	Decode Ways	O(n)	O(n)
90	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
91	Subsets	Subsets	O(2^n)	O(2^n)
92	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
93	Climbing Stairs	Climbing Stairs
94	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
95	Unique Paths	Unique Paths	O(n^2)	O(n^2)
96	Unique Paths II	Unique Paths II
97	Jump Game	Jump Game	O(n^2)	O(1)
98	N-Queens	N-Queens	O(n!)	O(n!)
99	Group Anagrams	Group Anagrams	O(n)	O(n)
100	Permutations	Permutations	O(n!)	O(n!)
101	Count and Say	Count and say	O(2^n)	O(n)
102	Combination Sum	Combination Sum	O(2^n)	O(n)
103	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
104	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
105	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
106	3Sum	3Sum	O(n^2)	O(n)
107	3Sum Closest	3Sum Closest	O(n^2)	O(1)
108	Roman to Integer	Roman to Integer	O(n)	O(1)
109	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
110	Add Two Numbers	Add Two Numbers	O(n)	O(n)
111	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
112	Single Number	Single Number
113	Reverse Bits	Reverse bits	O(1)	O(1)
114	Happy Number	Happy Number
115	Contains Duplicate II	Contains Duplicate II
116	Contains Duplicate III	Contains Duplicate III
117	Basic Calculator II	Basic Calculator II
118	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
119	Reverse Nodes in k-Group	Reverse Nodes in k-Group
120	Sudoku Solver	Sudoku Solver
121	Multiply Strings	Multiply Strings
122	Sort Colors	Sort Colors
123	Course Schedule	Course Schedule	O(n)	O(n)
124	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
125	Perfect Rectangle	Perfect Rectangle
126	Jump Game II	Jump Gmae II
127	Course Schedule III	Course Schedule III
128	Permutations II	Permutations II
129	Find All Duplicates in an Array	Find All Duplicates in an Array
130	Excel Sheet Column Title	Excel Sheet Column Title
131	Reverse Words in a String	Reverse Words in a String
132	Strobogrammatic Number	Strobogrammatic Number
133	Search a 2D Matrix	Search a 2D Matrix
134	Check If N and Its Double Exist	Check If N and Its Double Exist	O(n)	O(n)
135	Longest Word in Dictionary	Longest Word in Dictionary
136	Determine if Two Events Have Conflict	Determine if Two Events Have Conflict
137	Largest Number	Largest Number
138	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
139	Guess Number Higher or Lower	Guess Number Higher or Lower
140	Number of Enclaves	Number of Enclaves
141	Walls And Gates	Walls And Gates
142	Island Perimeter	Island Perimeter
143	Flood fill	Flood fill
144	Find if Path Exists in Graph	Find if Path Exists in Graph
145	Tree Diameter	Tree Diameter	O(n)	O(n)
146	Symmetric Tree	Symmetric Tree	O(n)	O(n)
147	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
148	Minimum Obstacle Removal to Reach Corner	Minimum Obstacle Removal to Reach Corner	O(n^2)	O(n)
149	Number of Islands	Number of Islands	O(n^2)	O(n^2)
150	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
151	Jump Game III	Jump Game III	O(n)	O(n)
152	Kill process	Kill process	O(n)	O(n)
153	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
154	Brace Expansion	Brace Expansion	O(2^n)	O(2^n)
155	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
156	4Sum	4Sum	O(n^2)	O(n)
157	Binary Search	Binary Search	O(log n)	O(1)
158	Minimum Number of Operations to Convert Time	Minimum Number of Operations to Convert Time	O(n)	O(1)
159	Destination City	Destination City	O(n)	O(n)

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Number of Islands	Number of Islands	O(n^2)	O(n^2)
2	Valid Number	Valid Number
3	Paint House	Paint House
4	Valid Palindrome	Valid Palindrome	O(n)	O(n)
5	Valid Parentheses	Valid Parentheses	O(n)	O(n)
6	Same Tree	Same Tree	O(log n)	O(1)
7	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
8	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
9	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
10	Maximum Subarray	Maximum Subarray	O(n)	O(n)
11	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
12	Shortest Word Distance	Shortest Word Distance
13	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
14	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
15	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
16	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
17	Word Break	Word Break	O(n^2)	O(n)
18	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
19	Word Ladder	Word Ladder	O(n^2)	O(n^2)
20	House Robber	House Robber	O(n)	O(1)
21	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
22	Climbing Stairs	Climbing Stairs	O(n)	O(n)
23	Insert Interval	Insert Interval	O(n)	O(n)
24	Merge Intervals	Merge Intervals	O(n log n)	O(n)
25	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
26	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
27	Permutations	Permutations	O(n!)	O(n!)
28	Combination Sum	Combination Sum	O(2^n)	O(n)
29	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
30	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
31	3Sum	3Sum	O(n^2)	O(n)
32	Roman to Integer	Roman to Integer	O(n)	O(1)
33	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
34	Two Sum	Two Sum	O(n)	O(n)
35	Basic Calculator	Basic Calculator
36	Basic Calculator II	Basic Calculator II
37	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
38	Subarray Sum Equals K	Subarray Sum Equals K
39	Reverse Words in a String	Reverse Words in a String
40	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
41	Symmetric Tree	Symmetric Tree	O(n)	O(n)
42	4Sum	4Sum	O(n^2)	O(n)

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
2	Remove Duplicates from Sorted Array	Remove Duplicates from Sorted Array
3	Interval List Intersections	Interval List Intersections
4	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
5	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
6	Best Time to Buy and Sell Stock III	Best Time to Buy and Sell Stock III	O(n)	O(1)
7	Best Time to Buy and Sell Stock IV	Best Time to Buy and Sell Stock IV	O(n^2)	O(n^2)
8	Move Zeroes	Move Zeroes
9	Roman to Integer	Roman to Integer	O(n)	O(1)
10	Merge Intervals	Merge Intervals	O(n log n)	O(n)
11	Insert Interval	Insert Interval	O(n)	O(n)
12	Valid Palindrome II	Valid Palindrome II
13	Valid Parentheses	Valid Parentheses	O(n)	O(n)
14	Plus One	Plus One
15	Maximal Square	Maximal Square	O(n^2)	O(n^2)
16	3Sum	3Sum	O(n^2)	O(n)
17	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
18	Word Break	Word Break	O(n^2)	O(n)
19	Number of Islands	Number of Islands	O(n^2)	O(n^2)
20	Course Schedule	Course Schedule	O(n)	O(n)
21	Maximum Subarray	Maximum Subarray	O(n)	O(n)
22	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
23	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
24	Minimum Window Substring	Minimum Window Substring	O(n)	O(n)
25	Binary Tree Level Order Traversal	Binary Tree Level Order Traversal	O(n)	O(n)
26	Clone Graph	Clone Graph	O(n)	O(n)
27	Kth Smallest Element in a BST	Kth Smallest Element in a BST	O(n)	O(n)
28	Encode and Decode Strings	Encode and Decode Strings	O(n)	O(n)
29	Design Add and Search Words Data Structure	Design Add and Search Words Data Structure	O(n)	O(n)
30	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
31	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
32	Binary Tree Maximum Path Sum	Binary Tree Maximum Path Sum	O(n)	O(n)
33	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
34	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
35	Longest Increasing Path in a Matrix	Longest Increasing Path in a Matrix
36	Subarray Sum Equals K	Subarray Sum Equals K
37	Valid Palindrome	Valid Palindrome	O(n)	O(n)
38	Target Sum	Target Sum
39	H-Index	H-Index
40	Count and Say	Count and say	O(2^n)	O(n)
41	Task Scheduler	Task Scheduler
42	Regular Expression Matching	Regular Expression Matching
43	Simplify Path	Simplify Path
44	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
45	Find All Anagrams in a String	Find All Anagrams in a String
46	Custom Sort String	Custom Sort String
47	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
48	Wildcard Matching	Wildvard Matching
49	Add Strings	Add Strings
50	First Bad Version	First Bad Version
51	Is Graph Bipartite?	Is Graph Bipartite?
52	Max Consecutive Ones III	Max Consecutive Ones III
53	K Closest Points to Origin	K Closest Points to Origin
54	Expression Add Operators	Expression Add Operators
55	Sudoku Solver	Sudoku Solver
56	Combination Sum	Combination Sum	O(2^n)	O(n)
57	Combination Sum IV	Combination Sum IV	O(2^n)	O(n)
58	Valid Number	Valid Number
59	Remove Invalid Parentheses	Remove Invalid Parentheses
60	Fraction to Recurring Decimal	Fraction to Recurring Decimal
61	Add Binary	Add Binary
62	Partition Equal Subset Sum	Partition Equal Subset Sum
63	Reverse Nodes in k-Group	Reverse Nodes in k-Group
64	Find the Index of the First Occurrence in a String	Find the Index of the First Occurrence in a String
65	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
66	Verifying an Alien Dictionary	Verifying an Alien Dictionary	O(n log n)	O(n)
67	Shortest Bridge	Shortest Bridge
68	Continuous Subarray Sum	Continuous Subarray Sum
69	Minimum Remove to Make Valid Parentheses	Minimum Remove to Make Valid Parentheses
70	Maximum Depth of Binary Tree	Maximum Depth of Binary Tree	O(n)	O(n)
71	Rotate Image	Rotate Image	O(n^2)	O(1)
72	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
73	Palindrome Permutation	Palindrome Permutation
74	Shortest Word Distance	Shortest Word Distance
75	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
76	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
77	Word Search	Word Search	O(n^2)	O(n)
78	Word Search II	Word Search II	O(n^2)	O(n^2)
79	Two Sum	Two Sum	O(n)	O(n)
80	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
81	Min Stack	Min Stack	O(n)	O(n)
82	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
83	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
84	Linked List Cycle	Linked List Cycle	O(n)	O(n)
85	Word Ladder	Word Ladder	O(n^2)	O(n^2)
86	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
87	Reverse Linked List	Reverse Linked List	O(n)	O(n)
88	House Robber	House Robber	O(n)	O(1)
89	Decode Ways	Decode Ways	O(n)	O(n)
90	Subsets	Subsets	O(2^n)	O(2^n)
91	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
92	Climbing Stairs	Climbing Stairs	O(n)	O(n)
93	Unique Paths	Unique Paths	O(n^2)	O(n^2)
94	Unique Paths II	Unique Paths II
95	Jump Game	Jump Game	O(n^2)	O(1)
96	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
97	N-Queens	N-Queens	O(n!)	O(n!)
98	Group Anagrams	Group Anagrams	O(n)	O(n)
99	Permutations	Permutations	O(n!)	O(n!)
100	Trapping Rain Water	Trapping Rain Water	O(n^2)	O(n)
101	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
102	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
103	Next Permutation	Next Permutation	O(n)	O(1)
104	Generate Parentheses	Generate Parentheses	O(2^n)	O(2^n)
105	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
106	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
107	Add Two Numbers	Add Two Numbers	O(n)	O(n)
108	Daily Temperatures	Daily Temperatures
109	Basic Calculator	Basic Calculator
110	Single Number	Single Number
111	Reverse Bits	Reverse bits	O(1)	O(1)
112	Happy Number	Happy Number
113	Contains Duplicate II	Contains Duplicate II
114	Basic Calculator II	Basic Calculator II
115	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
116	Reverse Nodes in k-Group	Reverse Nodes in k-Group
117	Multiply Strings	Multiply Strings
118	Sort Colors	Sort Colors
119	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
120	Find All Duplicates in an Array	Find All Duplicates in an Array
121	Excel Sheet Column Title	Excel Sheet Column Title
122	Reverse Words in a String	Reverse Words in a String
123	Strobogrammatic Number	Strobogrammatic Number
124	Word Pattern	Word Pattern
125	Search a 2D Matrix	Search a 2D Matrix
126	Largest Number	Largest Number
127	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
128	Walls And Gates	Walls And Gates
129	Island Perimeter	Island Perimeter
130	Flood fill	Flood fill
131	Tree Diameter	Tree Diameter	O(n)	O(n)
132	Symmetric Tree	Symmetric Tree	O(n)	O(n)
133	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
134	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
135	Jump Game III	Jump Game III	O(n)	O(n)
136	4Sum	4Sum	O(n^2)	O(n)
137	Binary Search	Binary Search	O(log n)	O(1)

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Microsoft

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum	O(n)	O(n)
2	Add Two Numbers	Add Two Numbers	O(n)	O(n)
3	String to Integer (atoi)	String to Integer (atoi)	O(n)	O(1)
4	Roman to Integer	Roman to Integer	O(n)	O(1)
5	Merge Two Sorted Lists	Merge Two Sorted Lists	O(n)	O(n)
6	Merge k Sorted Lists	Merge k Sorted Lists	O(n log n)	O(1)
7	Number of 1 Bits	Number of 1 bits	O(log n)	O(1)
8	Missing Number	Missing Number	O(n)	O(1)
9	Remove Duplicates from Sorted Array	Remove Duplicates from Sorted Array
10	Merge Intervals	Merge Intervals	O(n log n)	O(n)
11	Valid Palindrome	Valid Palindrome	O(n)	O(n)
12	Valid Parentheses	Valid Parentheses	O(n)	O(n)
13	Linked List Cycle	Linked List Cycle	O(n)	O(n)
14	Reverse Linked List	Reverse Linked List	O(n)	O(n)
15	3Sum	3Sum	O(n^2)	O(n)
16	Longest Palindromic Substring	Longest Palindromic Substring	O(n^2)	O(1)
17	Search in Rotated Sorted Array	Search in Rotated Sorted Array	O(log n)	O(1)
18	Number of Islands	Number of Islands	O(n^2)	O(n^2)
19	Maximum Subarray	Maximum Subarray	O(n)	O(n)
20	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
21	Spiral Matrix	Spiral Matrix	O(n^2)	O(n^2)
22	Product of Array Except Self	Product of Array Except Self	O(n)	O(n)
23	Jump Game	Jump Game	O(n^2)	O(1)
24	Implement Trie (Prefix Tree)	Implement Trie (Prefix Tree)	O(n)	O(n)
25	Word Search II	Word Search II	O(n^2)	O(n^2)
26	Binary Tree Maximum Path Sum	Binary Tree Maximum Path Sum	O(n)	O(n)
27	The Skyline Problem	The Skyline Problem	O(n log n)	O(n)
28	Rotate Array	Rotate Array
29	Reverse Nodes in k-Group	Reverse Nodes in k-Group
30	Binary Search Tree Iterator	Binary Search Tree Iterator	O(n)	O(n)
31	Add Digits	Add Digits
32	Median of Two Sorted Arrays	Median of Two Sorted Arrays	O(n)	O(n)
33	Kth Largest Element in an Array	Kth Largest Element in an Array	O(n log n)	O(n)
34	Valid Anagram	Valid Anagram	O(n)	O(n)
35	Container With Most Water	Container With Most Water	O(n)	O(1)
36	Longest Substring Without Repeating Characters	Longest Substring Without Repeating Characters	O(n)	O(n)
37	Rotate Image	Rotate Image	O(n^2)	O(1)
38	Word Search	Word Search	O(n^2)	O(n)
39	Word Break	Word Break	O(n^2)	O(n)
40	Coin Change	Coin Change	O(n^2)	O(n)
41	Palindrome Permutation	Palindrome Permutation
42	Search a 2D Matrix II	Search a 2D Matrix II	O(n)	O(1)
43	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
44	Sliding Window Maximum	Sliding Window Maximum	O(n)	O(n)
45	Maximal Square	Maximal Square	O(n^2)	O(n^2)
46	Two Sum II - Input array is sorted	Two Sum II - Input Array Is Sorted	O(n)	O(n)
47	Fraction to Recurring Decimal	Fraction to Recurring Decimal
48	Min Stack	Min Stack	O(n)	O(n)
49	Find Minimum in Rotated Sorted Array	Find Minimum in Rotated Sorted Array	O(log n)	O(1)
50	Maximum Product Subarray	Maximum Product Subarray	O(n)	O(n)
51	Clone Graph	Clone Graph	O(n)	O(n)
52	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
53	Longest Consecutive Sequence	Longest Consecutive Sequence	O(n log n)	O(1)
54	Pascal's Triangle	Pascal's Triangle	O(n^2)	O(n^2)
55	Pascal's Triangle II	Pascal's Triangle II	O(n^2)	O(n^2)
56	Count Primes	Count Primes	O(n log n)	O(n log n)
57	House Robber	House Robber	O(n)	O(1)
58	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
59	Decode Ways	Decode Ways	O(n)	O(n)
60	Subsets	Subsets	O(2^n)	O(2^n)
61	Set Matrix Zeroes	Set Matrix Zeroes	O(n^2)	O(n)
62	Climbing Stairs	Climbing Stairs	O(n)	O(n)
63	Minimum Path Sum	Minmum Path Sum	O(n^2)	O(1)
64	Unique Paths	Unique Paths	O(n^2)	O(n^2)
65	Unique Paths II	Unique Paths II
66	Insert Interval	Insert Interval	O(n)	O(n)
67	N-Queens	N-Queens	O(n!)	O(n!)
68	Pow(x, n)	Pow(x, n)	O(log n)	O(log n)
69	Group Anagrams	Group Anagrams	O(n)	O(n)
70	Combination Sum	Combination Sum	O(2^n)	O(n)
71	Count and Say	Count and say	O(2^n)	O(n)
72	Valid Sudoku	Valid Sudoku	O(n^2)	O(n)
73	Longest Valid Parentheses	Longest Valid Parentheses	O(n)	O(n)
74	Next Permutation	Next Permutation	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
76	Letter Combinations of a Phone Number	Letter Combinations of a Phone Number	O(2^n)	O(2^n)
77	3Sum Closest	3Sum Closest	O(n^2)	O(1)
78	Daily Temperatures	Daily Temperatures
79	Game of Life	Game of Life
80	Regular Expression Matching	Regular Expression Matching
81	Wildcard Matching	Wildvard Matching
82	Single Number	Single Number
83	Reverse Bits	Reverse bits	O(1)	O(1)
84	Happy Number	Happy Number
85	Contains Duplicate II	Contains Duplicate II
86	Basic Calculator II	Basic Calculator II
87	Alien Dictionary	Alien Dictionary	O(n log n)	O(n)
88	Add Strings	Add Strings
89	Sudoku Solver	Sudoku Solver
90	Multiply Strings	Multiply Strings
91	Sort Colors	Sort Colors
92	Course Schedule	Course Schedule	O(n)	O(n)
93	Move Zeroes	Move Zeroes
94	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)
95	Subarray Sum Equals K	Subarray Sum Equals K
96	Maximum Number of Balloons	here
97	Jump Game II	Jump Gmae II.
98	Course Schedule III	Course Schedule III
99	Find All Duplicates in an Array	Find All Duplicates in an Array
100	Excel Sheet Column Title	Excel Sheet Column Title
101	Reverse Words in a String	Reverse Words in a String
102	Strobogrammatic Number	Strobogrammatic Number
103	Word Pattern	Word Pattern
104	Search a 2D Matrix	Search a 2D Matrix
105	Largest Number	Largest Number
106	Invert Binary Tree	Invert Binary Tree	O(n)	O(1)
107	Walls And Gates	Walls And Gates
108	Find if Path Exists in Graph	Find if Path Exists in Graph
109	Tree Diameter	Tree Diameter	O(n)	O(n)
110	Symmetric Tree	Symmetric Tree	O(n)	O(n)
111	Binary Tree Vertical Order Traversal	Binary Tree Vertical Order Traversal	O(n)	O(n)
112	Cheapest Flights Within K Stops	Cheapest Flights Within K Stops	O(n^2)	O(n)
113	Jump Game III	Jump Game III	O(n)	O(n)
114	Kill process	Kill process	O(n)	O(n)
115	Surrounded Regions	Surrounded Regions	O(n^2)	O(1)
116	Count Complete Tree Nodes	Count Complete Tree Nodes	O(log n)	O(log n)
117	4Sum	4Sum	O(n^2)	O(n)
118	Binary Search	Binary Search	O(log n)	O(1)

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Netflix

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Department Top Three Salaries	Department Top Three Salaries
2	Valid Parentheses	Valid Parentheses	O(n)	O(n)
3	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
4	Merge Intervals	Merge Intervals	O(n log n)	O(n)
5	Group Anagrams	Group Anagrams	O(n)	O(n)
6	Top K Frequent Elements	Top K Frequent Elements	O(n)	O(n)

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Reddit

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Combination Sum	Combination Sum	O(2^n)	O(n)
2	Combination Sum II	Combination Sum II
3	Number of Islands	Number of Islands	O(n^2)	O(n^2)
4	Merge Sorted Array	Merge Sorted Array	O(n)	O(n)
5	Subsets	Subsets	O(2^n)	O(2^n)
6	Insert Interval	Insert Interval	O(n)	O(n)
7	Daily Temperatures	Daily Temperatures
8	Merge Intervals	Merge Intervals	O(n log n)	O(n)
9	Best Time to Buy and Sell Stock	Best Time to Buy and Sell Stock	O(n)	O(1)
10	Basic Calculator	Basic Calculator
11	Lowest Common Ancestor of a Binary Tree	Lowest Common Ancestor of a Binary Tree	O(n)	O(1)
12	Lowest Common Ancestor of a Binary Search Tree	Lowest Common Ancestor of a Binary Search Tree	O(n)	O(1)
13	Game of Life	Game of Life

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Spotify

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No.	Questions	Solution in PyCharm	Time Complexity	Space Complexity
1	Two Sum	Two Sum