LeetCode

This project starts at 2017.12.26 and It will keep updating in the next year.

Algorithms

• Bit Manipulation
• Array
• String
• Linked List
• Stack
• Queue
• Heap
• Tree
• Hash Table
• Math
• Two Pointers
• Sort
• Recursion
• Binary Search
• Binary Search Tree
• Breadth-First Search
• Depth-First Search
• Backtracking
• Dynamic Programming
• Greedy
• Geometry
• Design

Bit Manipulation

Title	Difficulty	C++	Python	Go	Tag	Note
Single Number
Single Number II
Single Number III
Power of Two
Power of Four
Missing Number
Number of 1 Bits
Reverse Bits
Majority Element
Sum of Two Integers
Find the Difference
Binary Watch
Convert a Number to Hexadecimal
Hamming Distance

Array

Title	Difficulty	C++	Python	Go	Tag	Note

String

Title	Difficulty	C++	Python	Go	Tag	Note
Simplify Path	Medium					split

Linked List

Title	Difficulty	C++	Python	Go	Tag	Note
Middle of the Linked List	Easy	C++				two pointers
Remove Linked List Elements	Easy	C++
Remove Duplicates from Sorted List	Easy	C++
Remove Duplicates from Sorted List II	Medium	C++
Remove Nth Node From End of List	Medium	C++				two pointers
Merge Two Sorted Lists	Easy			Go
Merge k Sorted Lists	Hard
Linked List Cycle	Easy	C++				two pointers
Linked List Cycle II	Medium	C++				two pointers
Intersection of Two Linked Lists	Easy	C++
Add Two Numbers	Medium	C++
Add Two Numbers II	Medium	C++				stack
Reverse Linked List	Easy	C++
Reverse Linked List II	Medium	C++
Reverse Nodes in k-Group	Hard
Reorder List	Medium			Go
Sort List	Medium			Go	sort	Merge-Sort
Insertion Sort List	Medium	C++			sort
Palindrome Linked List	Medium
Odd Even Linked List	Medium
Swap Nodes in Pairs	Medium
Copy List with Random Pointer	Medium
Partition List	Medium
Rotate List	Medium

Stack

Title	Difficulty	C++	Python	Go	Tag	Note
Valid Parentheses	Easy	C++
Longest Valid Parentheses	Medium	C++
Min Stack
Flatten Nested List Iterator
Mini Parser
Basic Calculator	Hard	C++
Basic Calculator II	Medium	C++
Basic Calculator III	Hard	C++
Evaluate Reverse Polish Notation	Medium
Remove Duplicate Letters
Verify Preorder Serialization of a Binary Tree
Container With Most Water	Medium	C++
Trapping Rain Water	Hard	C++
Largest Rectangle in Histogram	Hard	C++
Maximal Rectangle	Hard	C++
Decode String
Remove K Digits
132 Pattern
Next Greater Element I
Next Greater Element II
Tag Validator
Exclusive Time of Functions
Baseball Game
Number of Atoms
Daily Temperatures
Backspace String Compare
Car Fleet
Score of Parentheses
Decoded String at Index
Maximum Frequency Stack
Online Stock Span
Sum of Subarray Minimums

Queue

Title	Difficulty	C++	Python	Go	Tag	Note
Number of Recent Calls	Easy
Design Circular Queue	Medium
Design Circular Deque	Medium
Task Scheduler	Medium
Max Sum of Rectangle No Larger Than K	Hard
Shortest Subarray with Sum at Least K	Hard

Heap

Title	Difficulty	C++	Python	Go	Tag	Note
Top K Frequent Elements
Top K Frequent Words
Kth Largest Element in an Array
Merge k Sorted Lists
Reorganize String
Cheapest Flights Within K Stops
Kth Largest Element in a Stream
Reorganize String
K-th Smallest Prime Fraction
Find K-th Smallest Pair Distance
Split Array into Consecutive Subsequences
Design Twitter
Super Ugly Number
Ugly Number II
Sort Characters By Frequency

Tree

Title	Difficulty	C++	Python	Go	Tag	Note
Same Tree	Easy	C++
Symmetric Tree	Easy	C++
Balanced Binary Tree	Easy	C++
Minimum Depth of Binary Tree	Easy	C++
Maximum Depth of Binary Tree	Easy	C++
Binary Tree Preorder Traversal	Easy	C++
Binary Tree Inorder Traversal	Easy	C++
Binary Tree Postorder Traversal	Easy	C++
Binary Tree Level Order Traversal	Medium	C++				queue
Binary Tree Level Order Traversal II	Easy	C++				queue
Binary Tree Zigzag Level Order Traversal	Medium	C++				queue
Construct Binary Tree from Preorder and Inorder Traversal	Medium	C++
Construct Binary Tree from Inorder and Postorder Traversal	Medium	C++
Construct Binary Tree from Preorder and Postorder Traversal	Medium	C++
Path Sum	Easy	C++
Path Sum II	Medium	C++				backtracking
Path Sum III	Easy	C++
Sum of Left Leaves
Insert into a Binary Search Tree	Medium	C++
Search in a Binary Search Tree	Easy	C++
Lowest Common Ancestor of a Binary Search Tree	Easy	C++
Binary Search Tree Iterator
Validate Binary Search Tree
Serialize and Deserialize BST
Delete Node in a BST
Trim a Binary Search Tree
Convert Sorted Array to Binary Search Tree
Find Mode in Binary Search Tree
Most Frequent Subtree Sum
Find Bottom Left Tree Value
Find Largest Value in Each Tree Row
Diameter of Binary Tree
Convert BST to Greater Tree
Binary Tree Tilt
Subtree of Another Tree
Merge Two Binary Trees
Average of Levels in Binary Tree
Add One Row to Tree
Find Duplicate Subtrees
Two Sum IV - Input is a BST
Maximum Binary Tree
Print Binary Tree
Maximum Width of Binary Tree
Trim a Binary Search Tree
Second Minimum Node In a Binary Tree
Redundant Connection
Redundant Connection II
Longest Univalue Path
Binary Tree Pruning
Sum of Distances in Tree
All Nodes Distance K in Binary Tree
Smallest Subtree with all the Deepest Nodes
N-ary Tree Postorder Traversal
N-ary Tree Preorder Traversal
N-ary Tree Level Order Traversal
Maximum Depth of N-ary Tree
Leaf-Similar Trees
All Possible Full Binary Trees
Increasing Order Search Tree

Graph

Title	Difficulty	C++	Python	Go	Tag	Note
Clone Graph
Evaluate Division
Network Delay Time
Redundant Connection
Redundant Connection II
Minimum Height Trees
Reconstruct Itinerary

Hash Table

Title	Difficulty	C++	Python	Go	Tag	Note

Math

Title	Difficulty	C++	Python	Go	Tag	Note

Sort

Title	Difficulty	C++	Python	Go	Tag	Note
Valid Anagram
H-Index
Sort Colors
Intersection of Two Arrays
Intersection of Two Arrays II
Sort List
Insertion Sort List
Largest Number
Merge Intervals
Reorganize String
Longest Word in Dictionary through Deleting
Maximum Gap
Insert Interval
Implement Trie (Prefix Tree)	Medium	C++		Go		Trie

Two Pointers

Title	Difficulty	C++	Python	Go	Tag	Note

Binary Search

Title	Difficulty	C++	Python	Go	Tag	Note
First Bad Version
Pow(x, n)
Sqrt(x)
Heaters
Search for a Range

Binary Search Tree

Title	Difficulty	C++	Python	Go	Tag	Note
Range Sum Query - Mutable
Count of Smaller Numbers After Self
The Skyline Problem
Reverse Pairs

Breadth-First Search

Title	Difficulty	C++	Python	Go	Tag	Note
Binary Tree Level Order Traversal
Binary Tree Level Order Traversal II
Binary Tree Zigzag Level Order Traversal
Binary Tree Right Side View
Perfect Squares
Surrounded Regions
Minimum Height Trees
Course Schedule
Clone Graph

Depth-First Search

Title	Difficulty	C++	Python	Go	Tag	Note
Path Sum
Path Sum II
Binary Tree Right Side View
Same Tree
Construct Binary Tree from Preorder and Inorder Traversal
Construct Binary Tree from Inorder and Postorder Traversal
Balanced Binary Tree
Minimum Depth of Binary Tree
Flatten Binary Tree to Linked List
Sum Root to Leaf Numbers
Binary Tree Maximum Path Sum
Number of Islands
Remove Invalid Parentheses
Longest Increasing Path in a Matrix

Recursion

Title	Difficulty	C++	Python	Go	Tag	Note
Longest Univalue Path	Easy
放平果	Medium	C++				分类讨论
Hanoi	Medium	C++
Partition to K Equal Sum Subsets	Medium
K-th Symbol in Grammar	Medium
Valid Tic-Tac-Toe State	Medium
All Possible Full Binary Trees	Medium
Number of Atoms	Hard
Special Binary String	Hard

Backtracking

Title	Difficulty	C++	Python	Go	Tag	Note
Red and Black	Medium	C++
Combination Sum	Medium	C++
Combination Sum II	Medium	C++
Combination Sum III	Medium	C++
Permutations	Medium	C++
Permutations II	Medium	C++
Subsets	Medium	C++
Subsets II	Medium	C++
N-Queens	Hard	C++
N-Queens II	Hard	C++
Sudoku Solver	Hard
Word Search	Medium
Word Search II	Hard
Restore IP Addresses	Medium
Palindrome Partitioning	Medium	C++
Wildcard Matching	Hard
Regular Expression Matching	Hard
Word Ladder	Medium
Word Ladder II	Hard
Additive Number	Medium
Binary Watch	Easy
Count Numbers with Unique Digits	Medium
Beautiful Arrangement	Medium
Letter Case Permutation	Easy

Dynamic Programming

Title	Difficulty	C++	Python	Go	Tag	Note
Climbing Stairs	Easy	C++	Python
Min Cost Climbing Stairs	Easy	C++
Edit Distance	Hard	C++
Longest Increasing Subsequence	Medium	C++
Maximum Length of Repeated Subarray	Medium	C++
Minimum Path Sum	Medium	C++
Unique Paths	Medium	C++
Unique Paths II	Medium	C++
Unique Binary Search Trees	Medium	C++
Unique Binary Search Trees II	Medium	C++
Triangle	Medium	C++
Charm Bracelet	Medium	C++				0/1背包问题
Coin Change	Medium	C++				完全背包问题
Coin Change 2	Medium	C++				完全背包问题
Perfect Squares	Medium	C++				0/1背包问题
Ones and Zeroes	Medium	C++				二维0/1背包问题
Maximal Square	Medium	C++
Maximal Rectangle	Hard
Can I Win	Medium	C++
Target Sum
Word Break	Medium	C++
Predict the Winner
Longest Palindromic Subsequence	Medium	C++
Longest Palindromic Substring	Medium	C++
Count Different Palindromic Subsequences
Cheapest Flights Within K Stops
Minimum ASCII Delete Sum for Two Strings
Partition to K Equal Sum Subsets
Knight Probability in Chessboard
Delete and Earn
Arithmetic Slices
Arithmetic Slices II - Subsequence
Decode Ways
Decode Ways II
Shopping Offers

Greedy

Title	Difficulty	C++	Python	Go	Tag	Note
Container With Most Water	Medium	C++
Jump Game	Medium
Jump Game II	Hard
Gas Station	Medium
Candy	Hard
Remove Duplicate Letters	Hard
Create Maximum Number	Hard
Patching Array	Hard
Queue Reconstruction by Height	Medium
Remove K Digits	Medium
Non-overlapping Intervals	Medium
Minimum Number of Arrows to Burst Balloons	Medium
Assign Cookies	Easy
IPO	Hard
Dota2 Senate	Medium
Split Array into Consecutive Subsequences	Medium
Monotone Increasing Digits	Medium
Partition Labels	Medium
Reorganize String	Medium
Lemonade Change	Easy
Delete Columns to Make Sorted	Medium
Boats to Save People	Medium
Walking Robot Simulation	Medium
Advantage Shuffle	Medium
Score After Flipping Matrix	Medium

Union Find

Title	Difficulty	C++	Python	Go	Tag	Note
Surrounded Regions	Medium
Number of Islands	Medium
Longest Consecutive Sequence	Hard
Accounts Merge	Medium
Friend Circles	Medium
Redundant Connection	Medium
Redundant Connection II	Hard
Couples Holding Hands	Hard
Swim in Rising Water	Hard
Bricks Falling When Hit	Hard
Similar String Groups	Hard
Minimize Malware Spread II	Hard

Geometry

Title	Difficulty	C++	Python	Go	Tag	Note
Erect the Fence	Hard	C++	Python			Monotone Chain

Design

Title	Difficulty	C++	Python	Go	Tag	Note
LRU Cache	Hard	C++	Python

SQL

Shell