Top 75 LeetCode Questions to Save Your Time

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Frank Luo edited this page Apr 22, 2022 · 3 revisions

Array

Two Sum - https://leetcode.com/problems/two-sum/
Best Time to Buy and Sell Stock - https://leetcode.com/problems/best-time-to-buy-and-sell-stock/
Contains Duplicate - https://leetcode.com/problems/contains-duplicate/
Product of Array Except Self - https://leetcode.com/problems/product-of-array-except-self/
Maximum Subarray - https://leetcode.com/problems/maximum-subarray/
Maximum Product Subarray - https://leetcode.com/problems/maximum-product-subarray/
Find Minimum in Rotated Sorted Array - https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/
Search in Rotated Sorted Array - https://leetcode.com/problems/search-in-rotated-sorted-array/
3Sum - https://leetcode.com/problems/3sum/
Container With Most Water - https://leetcode.com/problems/container-with-most-water/

Binary

Sum of Two Integers - https://leetcode.com/problems/sum-of-two-integers/
Number of 1 Bits - https://leetcode.com/problems/number-of-1-bits/
Counting Bits - https://leetcode.com/problems/counting-bits/
Missing Number - https://leetcode.com/problems/missing-number/
Reverse Bits - https://leetcode.com/problems/reverse-bits/

Dynamic Programming

Climbing Stairs - https://leetcode.com/problems/climbing-stairs/
Coin Change - https://leetcode.com/problems/coin-change/
Longest Increasing Subsequence - https://leetcode.com/problems/longest-increasing-subsequence/
Longest Common Subsequence -
Word Break Problem - https://leetcode.com/problems/word-break/
Combination Sum - https://leetcode.com/problems/combination-sum-iv/
House Robber - https://leetcode.com/problems/house-robber/
House Robber II - https://leetcode.com/problems/house-robber-ii/
Decode Ways - https://leetcode.com/problems/decode-ways/
Unique Paths - https://leetcode.com/problems/unique-paths/
Jump Game - https://leetcode.com/problems/jump-game/

Graph

Clone Graph - https://leetcode.com/problems/clone-graph/
Course Schedule - https://leetcode.com/problems/course-schedule/
Pacific Atlantic Water Flow - https://leetcode.com/problems/pacific-atlantic-water-flow/
Number of Islands - https://leetcode.com/problems/number-of-islands/
Longest Consecutive Sequence - https://leetcode.com/problems/longest-consecutive-sequence/
Alien Dictionary (Leetcode Premium) - https://leetcode.com/problems/alien-dictionary/
Graph Valid Tree (Leetcode Premium) - https://leetcode.com/problems/graph-valid-tree/
Number of Connected Components in an Undirected Graph (Leetcode Premium) - https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/

Interval

Insert Interval - https://leetcode.com/problems/insert-interval/
Merge Intervals - https://leetcode.com/problems/merge-intervals/
Non-overlapping Intervals - https://leetcode.com/problems/non-overlapping-intervals/
Meeting Rooms (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms/
Meeting Rooms II (Leetcode Premium) - https://leetcode.com/problems/meeting-rooms-ii/

Linked List

Reverse a Linked List - https://leetcode.com/problems/reverse-linked-list/
Detect Cycle in a Linked List - https://leetcode.com/problems/linked-list-cycle/
Merge Two Sorted Lists - https://leetcode.com/problems/merge-two-sorted-lists/
Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
Remove Nth Node From End Of List - https://leetcode.com/problems/remove-nth-node-from-end-of-list/
Reorder List - https://leetcode.com/problems/reorder-list/

Matrix

Set Matrix Zeroes - https://leetcode.com/problems/set-matrix-zeroes/
Spiral Matrix - https://leetcode.com/problems/spiral-matrix/
Rotate Image - https://leetcode.com/problems/rotate-image/
Word Search - https://leetcode.com/problems/word-search/

String

Longest Substring Without Repeating Characters - https://leetcode.com/problems/longest-substring-without-repeating-characters/
Longest Repeating Character Replacement - https://leetcode.com/problems/longest-repeating-character-replacement/
Minimum Window Substring - https://leetcode.com/problems/minimum-window-substring/
Valid Anagram - https://leetcode.com/problems/valid-anagram/
Group Anagrams - https://leetcode.com/problems/group-anagrams/
Valid Parentheses - https://leetcode.com/problems/valid-parentheses/
Valid Palindrome - https://leetcode.com/problems/valid-palindrome/
Longest Palindromic Substring - https://leetcode.com/problems/longest-palindromic-substring/
Palindromic Substrings - https://leetcode.com/problems/palindromic-substrings/
Encode and Decode Strings (Leetcode Premium) - https://leetcode.com/problems/encode-and-decode-strings/

Tree

Maximum Depth of Binary Tree - https://leetcode.com/problems/maximum-depth-of-binary-tree/
Same Tree - https://leetcode.com/problems/same-tree/
Invert/Flip Binary Tree - https://leetcode.com/problems/invert-binary-tree/
Binary Tree Maximum Path Sum - https://leetcode.com/problems/binary-tree-maximum-path-sum/
Binary Tree Level Order Traversal - https://leetcode.com/problems/binary-tree-level-order-traversal/
Serialize and Deserialize Binary Tree - https://leetcode.com/problems/serialize-and-deserialize-binary-tree/
Subtree of Another Tree - https://leetcode.com/problems/subtree-of-another-tree/
Construct Binary Tree from Preorder and Inorder Traversal - https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/
Validate Binary Search Tree - https://leetcode.com/problems/validate-binary-search-tree/
Kth Smallest Element in a BST - https://leetcode.com/problems/kth-smallest-element-in-a-bst/
Lowest Common Ancestor of BST - https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/
Implement Trie (Prefix Tree) - https://leetcode.com/problems/implement-trie-prefix-tree/
Add and Search Word - https://leetcode.com/problems/add-and-search-word-data-structure-design/
Word Search II - https://leetcode.com/problems/word-search-ii/

Heap

Merge K Sorted Lists - https://leetcode.com/problems/merge-k-sorted-lists/
Top K Frequent Elements - https://leetcode.com/problems/top-k-frequent-elements/
Find Median from Data Stream - https://leetcode.com/problems/find-median-from-data-stream/