To learn the knowledge about data structures and algorithms. All the codes are in my Code-Camp.

Array & String

Easy

  •   13. Roman to Integer
  •   283. Move Zeroes
  •   58. Length of Last Word
  •   257. Binary Tree Paths
  •   26. Remove Duplicates from Sorted Array
  •   205. Isomorphic Strings
  •   28. Implement strStr()
  •   53. Maximum Subarray
  •   121. Best Time to Buy and Sell Stock

Medium

  •   609. Find Duplicate File in System
  •   45. Jump Game II

Hashmap & Hashtable

Easy

  •   169. Majority Element
  •   290. Word Pattern
  •   202. Happy Number
  •   217. Contains Duplicate
  •   141. Linked List Cycle
  •   1. Two Sum
  •   242. Valid Anagram
  •   349. Intersection of Two Arrays

Medium

  •   208. Implement Trie (Prefix Tree)
  •   138. Copy List with Random Pointer

Tree

Easy

  •   112. Path Sum
  •   226. Invert Binary Tree
  •   101. Symmetric Tree
  •   110. Balanced Binary Tree
  •   104. Maximum Depth of Binary Tree

Stack & Heap

Easy

  •   20. Valid Parentheses(Stack)
  •   225. Implement Stack using Queues(Stack)
  •   215. Kth Largest Element in an Array(Heap)
  •   1046. Last Stone Weight (Heap)

Reference

  1. A good sharing answer of LeetCode

  2. leetcode helper by Harry