Blind 75

The essential 75 LeetCode questions for interview prep

75 problems•9 sections

#	Problem	Difficulty
1	3Sum0 - Find three elements in an array that sum to a zero	medium
2	Best Time To Buy And Sell Stock 1 - only one transaction	easy
3	Container With Most Water	medium
4	Contains Duplicate 1 - Check if array has duplicates	easy
5	Encode and Decode Strings	medium
6	Find Minimum in Rotated Sorted Array	medium
7	Group Anagrams	medium
8	Longest Palindromic Substring	medium
9	Longest Substring with Same Letters after Replacement	medium
10	Longest Substring Without Repeating Characters	medium
11	Maximum Product Subarray	medium
12	Maximum Subarray Sum	medium
13	Minimum Window Substring	hard
14	Palindromic Substrings	medium
15	Product of Array Except Self	medium
16	Search in Rotated Sorted Array	medium
17	Two Sum	easy
18	Valid Anagram	easy
19	Valid Palindrome	easy
20	Valid Parentheses	easy

#	Problem	Difficulty	Video
1	Alien Dictionary	hard	-
2	Clone Undirected Graph	medium
3	Course Schedule 1 - Is it Possible	medium	-
4	Graph Valid Tree	medium	-
5	Longest Consecutive Sequence	medium
6	Number of Connected Components in an Undirected Graph	medium	-
7	Number of Islands	medium
8	Pacific Atlantic Water Flow	medium	-

#	Problem	Difficulty
1	Binary Tree Level Order Traversal - Level by Level	medium
2	Binary Tree Path Sum - Maximum between any two nodes	hard
3	Construct Binary Tree from Inorder and Preorder Traversal	medium
4	Design Add and Search Words Data Structure	medium
5	Implement Trie	medium
6	Invert Binary Tree	easy
7	Kth Smallest Element in a BST	medium
8	Lowest Common Ancestor of a Binary Search Tree	medium
9	Maximum Depth of Binary Tree	easy
10	Same Tree	easy
11	Serialize and Deserialize Binary Tree	hard
12	Subtree of Another Tree	easy
13	Validate Binary Search Tree	medium
14	Word Search 2 - Return All Words	hard

#	Problem	Difficulty
1	Climbing Stairs - Take atmost 2 Steps	easy
2	Coin Change with Fewest Number of Coins Given Infinite Supply	medium
3	Combination Sum 1	medium
4	Decode Ways	medium
5	House Robber 2 - Houses in circle	medium
6	House Robber	medium
7	Jump Game 1 - Check if it reaches last index	medium
8	Longest Common Subsequence LCS 1 - Get Length	medium
9	Longest Increasing Subsequence	medium
10	Unique Paths in Grid 1 - Count all paths moving right or down	medium
11	Word Break 1 - Check if word is breakable	medium

#	Problem	Difficulty
1	Counting Bits	easy
2	Missing Number	easy
3	Number of 1 Bits	easy
4	Reverse Bits	easy
5	Sum of Two Integers	medium

#	Problem	Difficulty	Video
1	Find Median from Data Stream	hard
2	Top K Frequent Elements	medium

#	Problem	Difficulty
1	Insert Interval	medium
2	Maximum Intervals Overlap Count	medium
3	Meeting Rooms 1 - Can person attend all meetings	easy
4	Merge Overlapping Intervals	medium
5	Non-overlapping Intervals	medium

#	Problem	Difficulty
1	Linked List Cycle 1 - Detect Cycle	easy
2	Merge K Sorted Lists	hard
3	Merge Two Sorted Linked Lists	easy
4	Remove Nth Node From End of List	medium
5	Reorder List such that i-th element points to n-i-th element	medium
6	Reverse Linked List	easy

#	Problem	Difficulty
1	Rotate n x n matrix by 90 degrees	medium
2	Set Matrix Zeros	medium
3	Spiral Matrix 1 - Return	medium
4	Word Search 1 - Find if word exists	medium

Arrays & Hashing