Little Algorithm

This repository contains the article index and reference solutions for my "LeetCode Explained with Examples" course. The article series was originally published on my WeChat public account in 2020.

English | 简体中文

How to use this repository

• Learn LeetCode problem-solving systematically:
  • The recommended reading experience is the website version: https://nettee.io/courses/algorithm
• Find reference code by LeetCode problem:
  • Look up a LeetCode problem in the table below to find the corresponding reference code and article link

Reference solutions

ID	Problem	Solution	Article
11	Container With Most Water	Java	Container With Most Water (Reservoir Problem)
19	Remove Nth Node From End of List	Java	Two Pointers × Linked List Problems: Fast and Slow Pointers
39	Combination Sum	Java	Solving the Combination Sum Series with One Template
40	Combination Sum II	Java	Solving the Combination Sum Series with One Template
46	Permutations	Java	Permutation and Combination: Candidate Sets in Backtracking
47	Permutations II	Java	Revisiting Permutations and Combinations: Deduplication Strategies in Backtracking
53	Maximum Subarray	Java(1, 2, 3, 4, 5)	Maximum Subarray Sum: Dynamic Programming Techniques for Subarray Problems
72	Edit Distance	Java	Classic Dynamic Programming: Edit Distance
77	Combinations		Permutation and Combination: Candidate Sets in Backtracking
78	Subsets	Java	From Binary Tree Traversal to Backtracking
90	Subsets II	Java	Revisiting Permutations and Combinations: Deduplication Strategies in Backtracking
98	Validate Binary Search Tree	Java	Converting a Binary Tree to a Linked List: Operating on Adjacent Nodes in Binary Tree Inorder Traversal
102	Binary Tree Level Order Traversal	Java	Use Cases for BFS: Level-Order Traversal and Shortest Path Problems
110	Balanced Binary Tree	Java	Diameter of Binary Tree: Global Variables in Binary Tree Traversal
112	Path Sum	Java	Path Sum: Subproblem Decomposition in Binary Trees
113	Path Sum II	Java	From Binary Tree Traversal to Backtracking
123	Best Time to Buy and Sell Stock III	Java	A Practical yet Elegant Approach to Stock Trading Problems
124	Binary Tree Maximum Path Sum	Java	Diameter of Binary Tree: Global Variables in Binary Tree Traversal
141	Linked List Cycle	Java	Two Pointers × Linked List Problems: Fast and Slow Pointers
148	Sort List	Java	Linked List Comprehensive Problem: Sorting a Linked List
167	Two Sum II - Input array is sorted	Java	Solving Two Sum with Two Pointers: Reducing the Search Space
189	Rotate Array	Java	The Power of Basic Operations: Reverse as an Example
198	House Robber	Java	House Robber: Four Steps to Solving Dynamic Programming Problems
206	Reverse Linked List	Java	Reverse Linked List: How to Easily Restructure a Linked List
216	Combination Sum III	Java	Solving the Combination Sum Series with One Template
240	Search a 2D Matrix II	Java	Solving Two Sum with Two Pointers: Reducing the Search Space
242	Valid Anagram	Java	The Anagram Problem: The Power of Basic Data Structures
303	Range Sum Query - Immutable	Java	Prefix Sum: A Space-for-Time Technique
322	Coin Change	Java	Classic Dynamic Programming: Three Coin Change Problems Explained
377	Combination Sum IV	Java	Classic Dynamic Programming: Three Coin Change Problems Explained
426	Convert Binary Search Tree to Sorted Doubly Linked List	Java	Converting a Binary Tree to a Linked List: Operating on Adjacent Nodes in Binary Tree Inorder Traversal
463	Island Perimeter	Java	Island Problems: DFS on Grid Structures
518	Coin Change 2	Java	Classic Dynamic Programming: Three Coin Change Problems Explained
543	Diameter of Binary Tree	Java	Diameter of Binary Tree: Global Variables in Binary Tree Traversal
560	Subarray Sum Equals K	Java	Prefix Sum: A Space-for-Time Technique
563	Binary Tree Tilt	Java	Diameter of Binary Tree: Global Variables in Binary Tree Traversal
695	Max Area of Island	Java	Island Problems: DFS on Grid Structures
718	Maximum Length of Repeated Subarray	Java	Maximum Subarray Sum: Dynamic Programming Techniques for Subarray Problems
724	Find Pivot Index	Java	Prefix Sum: A Space-for-Time Technique
827	Making A Large Island	Java	Island Problems: DFS on Grid Structures
876	Middle of the Linked List	Java	Two Pointers × Linked List Problems: Fast and Slow Pointers
978	Longest Turbulent Subarray	Java	Splitting Subproblems in Dynamic Programming to Simplify Your Approach
1143	Longest Common Subsequence	Java	Longest Common Subsequence: Solving with Two-Dimensional Dynamic Programming
1162	As Far from Land as Possible	Java	Use Cases for BFS: Level-Order Traversal and Shortest Path Problems
1372	Longest ZigZag Path in a Binary Tree	Java	Binary Tree Problems Too Complex? A Three-Step Method to Solve Them!
1373	Maximum Sum BST in Binary Tree	Java	Binary Tree Problems Too Complex? A Three-Step Method to Solve Them!