ximinng/LeetCode-notepad

LeetCode Notepad

JavaApache-2.0

LeetCode-notepad

Getting Started • About • Table of Contents • Acknowledgment • FAQ •

Made by Xing XiMing • 🌌 https://xingximing-xxm.github.io/

There are not only LeetCode solutions but also notes on various algorithm techniques.

Everything in this project is based on the Java language, using features such as the Java language paradigm.

Search for a specific Code. Can't find one? Please report a new Code here.

📋 Getting Started

Section #Getting Started contains one hundred popular interview problems, which is a good place to start.

LeetCode's TOP interview questions

#1 Two Sum
#2 Add Two Numbers
#3 Longest Substring Without Repeating Characters
#4 Median of Two Sorted Arrays
#5 Longest Palindromic Substring
#7 Reverse Integer
#8 String to Integer (atoi)
#10 Regular Expression Matching
#11 Container With Most Water
#13 Roman to Integer
#14 Longest Common Prefix
#15 3Sum
#17 Letter Combinations of a Phone Number
#19 Remove Nth Node From End of List
#20 Valid Parentheses
#21 Merge Two Sorted Lists
#22 Generate Parentheses
#23 Merge k Sorted Lists
#26 Remove Duplicates from Sorted Array
#45 Jump Game II
#55 Jump Game
#78 Subsets
#101 Symmetric Tree
#103 Binary Tree Zigzag Level Order Traversal
#104 Maximum Depth of Binary Tree
#121 Best Time to Buy and Sell Stock
#122 Best Time to Buy and Sell Stock II

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About

Summary of algorithm notes:

Sort
Math
Bit Manipulation
String
Two Pointers
Sliding Window
Binary search
Breadth First Search
Depth First Search
Graph
Backtracking
Greedy Algorithm
Dynamic Programming
- Knapsack problem
- Best Time to Buy and Sell Stock

Table of Contents

Section #Table of Contents contains the summary of the algorithm notes and all the problems.

Expand Set of LeetCode Problems

Sort

Math

#50 Pow(x,n)
#263 Ugly Number
#264 Ugly Number II
#914 X of a Kind in a Deck of Cards
#1201 Ugly Number III
#1227 Airplane Seat Assignment Probability
#1524 Number of Sub-arrays With Odd Sum
#1551 Minimum Operations to Make Array Equal

String

Two Pointers

#1 Two Sum
#9 Palindrome Number
#26 Remove Duplicates from Sorted Array
#19 Remove Nth Node From End of List

Sliding Window

#3 Longest Substring Without Repeating Characters

Array

#27 Remove Element
#35 Search Insert Position
#42 Trapping Rain Water
#66 Plus One
#73 Set Matrix Zeroes
#75 Sort Colors
#76 Minimum Window Substring
#80 Remove Duplicates from Sorted Array II
#81 Search in Rotated Sorted Array II
#125 Valid Palindrome
#167 Two Sum II - Input array is sorted
#344 Reverse String
#438 Find All Anagrams in a String
#485 Max Consecutive Ones
#567 Permutation in String
#1004 Max Consecutive Ones III
#1234 Replace the Substring for Balanced String

Matrix

#54 Spiral Matrix

LinkedList

#2 Add Two Numbers
#21 Merge Two Sorted Lists
#23 Merge k Sorted Lists
#25 Reverse Nodes in k-Group
#61 Rotate List
#92 Reverse Linked List II
#138 Copy List with Random Pointer
#141 Linked List Cycle
#142 Linked List Cycle II
#206 Reverse Linked List
#237 Delete Node in a Linked List
#876 Middle of the Linked List
#725 Split Linked List in Parts
#1171 Remove Zero Sum Consecutive Nodes from Linked List
#1290 Convert Binary Number in a Linked List to Integer
#1669 Merge In Between Linked Lists

Stack

#20 Valid Parentheses
#50 Pow(x,n)
#84 Largest Rectangle in Histogram
#94 Binary Tree Inorder Traversal
#144 Binary Tree Preorder Traversal
#145 Binary Tree Postorder Traversal
#1441 Build an Array With Stack Operations

Queue

#102 Binary Tree Level Order Traversal
#225 Implement Stack using Queues
#232 Implement Queue using Stacks
#239 Sliding Window Maximum
#622 Design Circular Queue
#641 Design Circular Deque
#933 Number of Recent Calls
#950 Reveal Cards In Increasing Order
#1306 Jump Game III
#1696 Jump Game VI

Binary Tree

#98 Validate Binary Search Tree
#103 Binary Tree Zigzag Level Order Traversal
#105 Construct Binary Tree from Preorder and Inorder Traversal
#114 Flatten Binary Tree to Linked List
#116 Populating Next Right Pointers in Each Node
#222 Count Complete Tree Nodes
#226 Invert Binary Tree
#230 Kth Smallest Element in a BST
#236 Lowest Common Ancestor of a Binary Tree
#297 Serialize and Deserialize Binary Tree
#341 Flatten Nested List Iterator
#450 Delete Node in a BST
#538 Convert BST to Greater Tree
#652 Find Duplicate Subtrees
#654 Maximum Binary Tree
#700 Search in a Binary Search Tree
#701 Insert into a Binary Search Tree
#814 Binary Tree Pruning
#938 Range Sum of BST

Trie

#208 Implement Trie (Prefix Tree)

Graph

BFS

Binary search

#4 Median of Two Sorted Arrays
#34 Find First and Last Position of Element in Sorted Array
#69 Sqrt(x)
#74 Search a 2D Matrix
#153 Find Minimum in Rotated Sorted Array
#154 Find Minimum in Rotated Sorted Array II
#704 Binary Search
#1482 Minimum Number of Days to Make m Bouquets

Backtracking

#17 Letter Combinations of a Phone Number
#22 Generate Parentheses
#46 Permutations
#51 N-Queens
#78 Subsets
#79 Word Search
#698 Partition to K Equal Sum Subsets

Greedy algorithm

#45 Jump Game II
#55 Jump Game
#435 Non-overlapping Intervals
#452 Minimum Number of Arrows to Burst Balloons
#781 Rabbits in Forest
#1024 Video Stitching
#1221 Split a String in Balanced Strings
#1431 Kids With the Greatest Number of Candies
#1403 Minimum Subsequence in Non-Increasing Order

Bit manipulation

#7 Reverse Integer
#1720 Decode XORed Array

Dynamic programming

#5 Longest Palindromic Substring
#53 Maximum Subarray
#72 Edit Distance
#87 Scramble String
#91 Decode Ways
#121 Best Time to Buy and Sell Stock
#122 Best Time to Buy and Sell Stock II
#123 Best Time to Buy and Sell Stock III
#188 Best Time to Buy and Sell Stock IV
#309 Best Time to Buy and Sell Stock with Cooldown
#714 Best Time to Buy and Sell Stock with Transaction Fee
#213 House Robber II
#300 Longest Increasing Subsequence
#322 Coin Change
#354 Russian Doll Envelopes
#583 Delete Operation for Two Strings
#1143 Longest Common Subsequence

Others

#12 Integer to Roman
#13 Roman to Integer

All the java code was tested under version 8 ✅.

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Acknowledgment

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💬 FAQ

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Git commit format:

git commit -m "feat/fix/docs(#problem_id): | Description:(unnecessary), Solution:(unnecessary)"

message	explain
feat	Commit a solution
fix	A bug fix
perf	A code change that improves performance
docs	Documentation only changes
test	Adding missing tests or correcting existing tests