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Introduction

Complete solutions to LeetCode, LCOF and LCCI problems, updated daily. Please give me a star 🌟 if you like it.

中文文档

Sites

• Vercel: https://doocs-leetcode.vercel.app
• GitHub Pages: https://doocs.github.io/leetcode

Solutions

• LeetCode
• Past Contests
• LCOF: Coding Interviews, 2nd Edition
• LCCI: Cracking the Coding Interview, 6th Edition

Topics

1. Basic Algorithms

• Find First and Last Position of Element in Sorted Array - Binary search
• Minimum Speed to Arrive on Time - Binary search
• Find the Student that Will Replace the Chalk - Binary search
• Maximum Number of Removable Characters - Binary search
• Sort an Array - Quick Sort, Merge Sort
• Add Strings - Addition of large numbers
• Multiply Strings - Multiply large numbers
• Range Sum Query - Immutable - Prefix sum
• Range Sum Query 2D - Immutable - Prefix sum
• Range Addition - Prefix sum, Difference array
• Stamping the Grid - Prefix sum, Difference array
• Longest Substring Without Repeating Characters - Two pointers, Hash table
• Subarray Product Less Than K - Two pointers
• Number of 1 Bits - Bit manipulation, Lowbit
• Merge Intervals - Merge intervals

2. Data Structures

• Design Linked List - Linked List, Pointer, Array
• Next Greater Element I - Monotonic Stack
• Daily Temperatures - Monotonic Stack
• Max Chunks To Make Sorted II - Monotonic Stack
• Sum of Subarray Minimums - Monotonic Stack
• Maximum Width Ramp - Monotonic Stack
• Sum of Subarray Ranges - Monotonic Stack
• Maximum Subarray Min-Product - Monotonic Stack
• Sliding Window Maximum - Monotonic Queue
• Max Value of Equation - Monotonic Queue
• Shortest Subarray with Sum at Least K - Monotonic Queue
• Constrained Subsequence Sum - Dynamic Programming, Monotonic Queue
• Word Pattern II - Hash Table、Backtracking
• Shortest Palindrome - Rabin-Karp
• Palindrome Pairs - Rabin-Karp
• Longest Duplicate Substring - Rabin-Karp, Binary search
• Distinct Echo Substrings - Rabin-Karp

3. Search

• Flood Fill - BFS, DFS, Flood fill
• Number of Islands - BFS, Flood fill
• 01 Matrix - BFS with multiple sources
• Map of Highest Peak - BFS with multiple sources
• Minimum Knight Moves - BFS, Shortest paths model
• Shortest Path in Binary Matrix - BFS, Shortest paths model
• Nearest Exit from Entrance in Maze - BFS, Shortest paths model
• Shortest Path in a Grid with Obstacles Elimination - BFS, Shortest paths model
• Open the Lock - Minimum steps model, Two-end BFS, A* search
• Word Ladder - Minimum steps model, Two-end BFS
• Minimum Operations to Convert Number - Minimum steps model, Two-end BFS
• Sliding Puzzle - BFS, Minimum steps model, A* search
• Shortest Path Visiting All Nodes - BFS, Minimum steps model, A* search
• Cut Off Trees for Golf Event - BFS, A* search
• Minimum Cost to Make at Least One Valid Path in a Grid - BFS using deque
• Minimum Cost to Make at Least One Valid Path in a Grid - BFS using deque
• The Maze - DFS, Flood fill
• Word Search - DFS, Backtracking
• Path with Maximum Gold - DFS, Backtracking
• Matchsticks to Square - DFS, Backtracking
• Partition to K Equal Sum Subsets - DFS, Backtracking
• Find Minimum Time to Finish All Jobs - DFS, Backtracking
• Fair Distribution of Cookies - DFS, Backtracking
• Longest Increasing Path in a Matrix - DFS、Memoization
• Number of Increasing Paths in a Grid - DFS、Memoization
• Flip Game II - DFS、Bitmask、Memoization
• Count All Possible Routes - DFS、Memoization
• Number of Ways of Cutting a Pizza - DFS、Memoization

4. Dynamic Programming(DP)

• Pascal's Triangle - Linear problem
• Minimum Path Sum - Linear problem
• Cherry Pickup - Linear problem
• Cherry Pickup II - Linear problem
• Longest Increasing Subsequence - Linear problem, LIS
• Non-overlapping Intervals - Linear problem, LIS, Greedy
• Delete Columns to Make Sorted III - Linear problem, LIS
• Russian Doll Envelopes - Linear problem, LIS
• Maximum Height by Stacking Cuboids - Sort, Linear problem, LIS
• Best Team With No Conflicts - Sort, Linear problem, LIS
• Longest Common Subsequence - Linear problem, LCS
• Minimum ASCII Delete Sum for Two Strings - Linear problem, LCS
• Delete Operation for Two Strings - Linear problem, LCS
• Target Sum - 0-1 Knapsack problem
• Partition Equal Subset Sum - 0-1 Knapsack problem
• Last Stone Weight II - 0-1 Knapsack problem
• Coin Change - Unbounded Knapsack problem
• Combination Sum IV - Unbounded Knapsack problem
• Maximum Value of K Coins From Piles - Group Knapsack problem
• Number of Digit One - Digit DP problem, Memoization
• Count Numbers with Unique Digits - Digit DP problem, Memoization
• Non-negative Integers without Consecutive Ones - Digit DP problem, Memoization
• Rotated Digits - Digit DP problem, Memoization
• Numbers At Most N Given Digit Set - Digit DP problem, Memoization
• Count Special Integers - Digit DP problem, Memoization

5. Advanced Data Structures

• Detect Cycles in 2D Grid - Union find, Detect cycles
• Evaluate Division - Union find
• Regions Cut By Slashes - Union find
• Swim in Rising Water - Union find
• Smallest String With Swaps - Union find
• Bricks Falling When Hit - Union find, Reversed thinking
• Minimize Malware Spread II - Union find, Reversed thinking
• Checking Existence of Edge Length Limited Paths - Union find, Offline algorithm
• Remove Max Number of Edges to Keep Graph Fully Traversable - Two Union find
• Range Sum Query - Mutable - Binary Indexed Tree, Segment Tree
• Create Sorted Array through Instructions - Binary Indexed Tree, Segment Tree
• Count Good Triplets in an Array - Binary Indexed Tree, Segment Tree
• Minimum Possible Integer After at Most K Adjacent Swaps On Digits - Binary Indexed Tree
• Range Sum Query 2D - Mutable - Binary Indexed Tree 2D, Segment Tree
• Count of Smaller Numbers After Self - Binary Indexed Tree, Discretization, Segment Tree
• Count of Range Sum - Binary Indexed Tree, Discretization, Segment Tree
• Reverse Pairs - Binary Indexed Tree, Discretization, Divide and Conquer, Segment Tree
• Number of Longest Increasing Subsequence - Binary Indexed Tree, Discretization, Interval maximum
• Fancy Sequence - Dynamic Segment Tree, Lazy Propogation
• Range Module - Dynamic Segment Tree, Lazy Propogation
• My Calendar III - Dynamic Segment Tree, Lazy Propogation
• Amount of New Area Painted Each Day - Dynamic Segment Tree, Lazy Propogation
• Longest Substring of One Repeating Character - Segment Tree
• Rectangle Area II - Segment Tree, Discretization, Line Sweep

6. Graph Theory

• Network Delay Time - Shortest Path, Dijkstra's algorithm, Bellman Ford's algorithm, SPFA
• Minimum Weighted Subgraph With the Required Paths - Shortest Path, Dijkstra's algorithm
• Min Cost to Connect All Points - Minimum Spanning Tree, Prim's algorithm, Kruskal's algorithm, Union find
• Connecting Cities With Minimum Cost - Minimum Spanning Tree, Kruskal's algorithm
• Optimize Water Distribution in a Village - Minimum Spanning Tree, Kruskal's algorithm, Union find
• Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree - Minimum Spanning Tree, Kruskal's algorithm, Union find
• Is Graph Bipartite? - Graph coloring, Union find

Contributions

I'm looking for long-term contributors/partners to this repo! Send me PRs if you're interested! See the following:

1. Fork this repository to your own GitHub account and then clone it to your local machine.
2. Checkout a new branch.
3. Make some changes to your leetcode repository, then push the changes to your remote GitHub repository.
4. Create a pull request with your changes!
5. See CONTRIBUTING or GitHub Help for more details.

You can also contribute to doocs/leetcode using Gitpod.io, a free online dev environment with a single click.

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License

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