My name is Wei Wang, a graduate student from Columbia University Engineering School, seeking 2022 summer intern and 2023 full-time software engineer job.
I will update the codes and notes after I solve every leetcode problem. These problems will be categorized by the algorithms.
2022.2.9 Update
#121 Best Time to Buy and Sell Stock
#217 Contains Duplicate
#238 Product of Array Except Self
2022.2.10 Update
#152 Maximum Product Subarray
#53 Maximum Subarray
2022.2.17 Update
#153 Find Minimum in Rotated Sorted Array
2022.2.18 Update
#33 Search in Rotated Sorted Array
#167 Two Sum II - Input Array Is Sorted
#15 3Sum
#11 Container With Most Water
2021.12.28 Update
Binary Search Fundamentals
#35 Search Insert Position
2021.12.30 Update
#34 Find First and Last Position of Element in Sorted Array
2021.12.29 Update
#27 Remove Element
2022.1.3 Update
#977 Squares of a Sorted Array
#209 Minimum Size Subarray Sum-Sliding Window
#3 Longest Substring Without Repeating Characters-Sliding Window
2022.1.6 Update
Sliding Window Notes
#19 Remove Nth Node From End of List
2022.2.14 Update
Two Pointers Fundamentals
2022.7.29 Update
#142 Linked List Cycle II
#76 Minimum Window Substring
2022.1.4 Update
#203 Remove Linked List Elements
2022.1.5 Update
#707 Design Linked List
2022.1.6 Update
#24 Swap Nodes in Pairs
#206 Reverse Linked List
#160 Intersection of Two Linked Lists
2022.1.6 Update
#242 Valid Anagram
#1002 Find Common Characters
#349 Intersection of Two Arrays
2022.1.7 Update
Hash Table Fundamentals
#202 Happy Number
#1 Two Sum
#454 4SumII
#383 Ransom Note
2022.2.16 Update:
#1347 Minimum Number of Steps to Make Two Strings Anagram
2022.2.20 Update
#128 Longest Consecutive Sequence
2022.7.20 Update
#49 Group Anagrams
2022.7.25 Update
#36 Valid Sudoku
2022.1.8 Update
Tree Fundamentals
#94 Binary Tree Inorder Traversal
#144 Binary Tree Preorder Traversal
#145 Binary Tree Postorder Traversal
#102 Binary Tree Level Order Traversal
2022.1.9 Update
#107 Binary Tree Level Order Traversal II
#199 Binary Tree Right Side View
#637 Average of Levels in Binary Tree
#429 N-ary Tree Level Order Traversal
#515 Find Largest Value in Each Tree Row
#116 Populating Next Right Pointers in Each Node
#117 Populating Next Right Pointers in Each Node II
#104 Maximum Depth of Binary Tree
#111 Minimum Depth of Binary Tree
#226 Invert Binary Tree
2022.1.10 Update
#101 Symmetric Tree
#222 Count Complete Tree Nodes
#110 Balanced Binary Tree
#257 Binary Tree Paths
#100 Same Tree
#404 Sum of Left Leaves
#513 Find Bottom Left Tree Value
#112 Path Sum
#113 Path Sum II
2022.1.11 Update
#106 Construct Binary Tree from Inorder and Postorder Traversal
#105 Construct Binary Tree from Preorder and Inorder Traversal
#654 Maximum Binary Tree
#617 Merge Two Binary Trees
2022.1.12 Update
#700 Search in a Binary Search Tree
#98 Validate Binary Search Tree
#530 Minimum Absolute Difference in BST
#501 Find Mode in Binary Search Tree
#236 Lowest Common Ancestor of a Binary Tree
2022.1.13 Update
#235 Lowest Common Ancestor of a Binary Search Tree
#701 Insert into a Binary Search Tree
#450 Delete Node in a BST
#669 Trim a Binary Search Tree
#108 Convert Sorted Array to Binary Search Tree
#538 Convert BST to Greater Tree
2022.1.13 Update
#232 Implement Queue using Stacks
#225 Implement Stack using Queues
2022.1.15 Update
#20 Valid Parentheses
#1047 Remove All Adjacent Duplicates In String
#150 Evaluate Reverse Polish Notation
#239 Sliding Window Maximum
#347 Top K Frequent Elements
2022.2.17 Update
#353 Design Snake Game
2022.1.16 Update
#344 Reverse String
#541 Reverse String II
#151 Reverse Words in a String
2022.1.17 Update
#28 Implement strStr()
#459 Repeated Substring Pattern
#409 Longest Palindrome
#647 Palindromic Substrings
#9 Palindrome Number
2022.1.21 Update
String Fundamentals
#58 Length of Last Word
#557 Reverse Words in a String III
2022.1.20 Update
#1275 Find Winner on a Tic Tac Toe Game
#146 LRU Cache
#1710 Maximum Units on a Truck
#200 Number of Islands
#253 Meeting Rooms II
#387 First Unique Character in a String
#56 Merge Intervals
#696 Count Binary Substrings
#937 Reorder Data in Log Files
2022.1.21 Update
#21. Merge Two Sorted Lists
#973 K Closest Points to Origin
#819 Most Common Word
#1876 Substrings of Size Three with Distinct Characters
#5 Longest Palindromic Substring
#1180 Count Substrings with Only One Distinct Letter
2022.1.22 Update
#2 Add Two Numbers
2022.1.23 Update
#1846 Maximum Element After Decreasing and Rearranging
#1492 The kth Factor of n
2022.1.22 Update
#77 Combinations
#216 Combination Sum III
#17 Letter Combinations of a Phone Number
2022.1.24 Update
#39 Combination Sum
#40 Combination Sum II
#131 Palindrome Partitioning
2022.1.25 Update
#93 Restore IP Addresses
#78 Subsets
#90 Subsets II
#491 Increasing Subsequences
#46 Permutations
#47 Permutations II
2022.1.22 Update
#455 Assign Cookies
#376 Wiggle Subsequence
#53 Maximum Subarray
2022.1.25 Update
#122 Best Time to Buy and Sell Stock II
#55 Jump Game
2022.1.26 Update
#1005 Maximize Sum Of Array After K Negations
#134 Gas Station
#135 Candy
#45 Jump Game II
#860 Lemonade Change
2022.1.27 Update
#406 Queue Reconstruction by Height
#435 Non-overlapping Intervals
#452 Minimum Number of Arrows to Burst Balloons
#714 Best Time to Buy and Sell Stock with Transaction Fee
#738 Monotone Increasing Digits
#763 Partition Labels
2022.1.27 Update
#70 Climbing Stairs
#509 Fibonacci Number
2022.1.28 Update
#343 Integer Break
#62 Unique Paths
#63 Unique Paths II
#746 Min Cost Climbing Stairs
#96 Unique Binary Search Trees
2022.1.29 Update
#1049 Last Stone Weight II
#416 Partition Equal Subset Sum
2022.1.30 Update
#377 Combination Sum IV
#474 Ones and Zeroes
#494 Target Sum
#518 Coin Change 2
2022.2.15 Update
#1048 Longest String Chain
2022.2.17 Update
#886 Possible Bipartition
2022.2.20 Update
#200 Number of Islands
#207 Course Schedule