## Array (33)

53. Maximum Subarray
867. Transpose Matrix
985. Sum of Even Numbers After Queries
1184. Distance Between Bus Stops
27. Remove Element
16. 3Sum Closest
448. Find All Numbers Disappeared in an Array
31. Next Permutation
289. Game of Life
134. Gas Station
55. Jump Game
56. Merge Intervals
48. Rotate Image
119. Pascal's Triangle II
118. Pascal's Triangle
28. Implement strStr()
41. First Missing Positive
26. Remove Duplicates from Sorted Array
914. X of a Kind in a Deck of Cards
454. 4Sum II
66. Plus One
18. 4Sum
495. Teemo Attacking
982. Triples with Bitwise AND Equal To Zero
189. Rotate Array
1031. Maximum Sum of Two Non-Overlapping Subarrays
33. Search in Rotated Sorted Array
15. 3Sum
73. Set Matrix Zeroes
88. Merge Sorted Array
238. Product of Array Except Self
287. Find the Duplicate Number
1. Two Sum

Time Management
Essays

## BFS (31)

854. K-Similar Strings
1302. Deepest Leaves Sum
3278. Catch That Cow
494. Target Sum
433. Minimum Genetic Mutation
1263. Minimum Moves to Move a Box to Their Target Location
117. Populating Next Right Pointers in Each Node II
116. Populating Next Right Pointers in Each Node
863. All Nodes Distance K in Binary Tree
787. Cheapest Flights Within K Stops
994. Rotting Oranges
785. Is Graph Bipartite?
559. Maximum Depth of N-ary Tree
429. N-ary Tree Level Order Traversal
752. Open the Lock
743. Network Delay Time
690. Employee Importance
542. 01 Matrix
133. Clone Graph
513. Find Bottom Left Tree Value
513. Find Bottom Left Tree Value
310. Minimum Height Trees
210. Course Schedule II
207. Course Schedule
200. Number of Islands
199. Binary Tree Right Side View
111. Minimum Depth of Binary Tree
107. Binary Tree Level Order Traversal II
103. Binary Tree Zigzag Level Order Traversal

## BST (1)

315. Count of Smaller Numbers After Self

## Backtracking (17)

131. Palindrome Partitioning
60. Permutation Sequence
52. N-Queens II
44. Wildcard Matching
37. Sudoku Solver
90. Subsets II
47. Permutations II
46. Permutations
40. Combination Sum II
39. Combination Sum
216. Combination Sum III
980. Unique Paths III
51. N-Queens
78. Subsets
22. Generate Parentheses

## Bash (4)

195. Tenth Line
194. Transpose File
193. Valid Phone Numbers
192. Word Frequency
378. Kth Smallest Element in a Sorted Matrix
240. Search a 2D Matrix II
4. Median of Two Sorted Arrays
35. Search Insert Position
6.6 最左原位
50. Pow(x, n)
34. Find First and Last Position of Element in Sorted Array
162. Find Peak Element
154. Find Minimum in Rotated Sorted Array II
74. Search a 2D Matrix
33. Search in Rotated Sorted Array
109. Convert Sorted List to Binary Search Tree
69. Sqrt(x)
153. Find Minimum in Rotated Sorted Array
300. Longest Increasing Subsequence
287. Find the Duplicate Number

## Bit Manipulation (12)

338. Counting Bits
371. Sum of Two Integers
268. Missing Number
191. Number of 1 Bits
190. Reverse Bits
169. Majority Element
29. Divide Two Integers
Bit Manipulation
389. Find the Difference
260. Single Number III
137. Single Number II
136. Single Number

## Books (12)

《学会提问》

Small Fry - 小人物：我和父亲乔布斯

## Classification (1)

Logistic Regression

Clustering

DBSCAN
K-Means

## Coding (449)

876. Middle of the Linked List
53. Maximum Subarray
1105. Filling Bookcase Shelves
Git
844. Backspace String Compare
854. K-Similar Strings
1171. Remove Zero Sum Consecutive Nodes from Linked List
195. Tenth Line
194. Transpose File
193. Valid Phone Numbers
192. Word Frequency
867. Transpose Matrix
1302. Deepest Leaves Sum
1301. Number of Paths with Max Score
985. Sum of Even Numbers After Queries
398. Random Pick Index
1184. Distance Between Bus Stops
1147. Longest Chunked Palindrome Decomposition
Word Count
664. Strange Printer
MapReduce 实现 K-Means
Learn MapReduce From Scratch
391. Perfect Rectangle
Search
Search
1290. Convert Binary Number in a Linked List to Integer

3278. Catch That Cow
264. Ugly Number II
263. Ugly Number
508. Most Frequent Subtree Sum
Cracking the Coding Interview 6th Ed.

45. Jump Game II
58. Length of Last Word
43. Multiply Strings
30. Substring with Concatenation of All Words
83. Remove Duplicates from Sorted List
9. Palindrome Number
24. Swap Nodes in Pairs
27. Remove Element
16. 3Sum Closest
6. ZigZag Conversion
312. Burst Balloons
406. Queue Reconstruction by Height
438. Find All Anagrams in a String
647. Palindromic Substrings
494. Target Sum
560. Subarray Sum Equals K
448. Find All Numbers Disappeared in an Array
617. Merge Two Binary Trees
739. Daily Temperatures
338. Counting Bits
31. Next Permutation
226. Invert Binary Tree
309. Best Time to Buy and Sell Stock with Cooldown
221. Maximal Square
395. Longest Substring with At Least K Repeating Characters
387. First Unique Character in a String
371. Sum of Two Integers
378. Kth Smallest Element in a Sorted Matrix
412. Fizz Buzz
384. Shuffle an Array
344. Reverse String
341. Flatten Nested List Iterator
347. Top K Frequent Elements
350. Intersection of Two Arrays II
349. Intersection of Two Arrays
315. Count of Smaller Numbers After Self
324. Wiggle Sort II
326. Power of Three
295. Find Median from Data Stream
283. Move Zeroes
236. Lowest Common Ancestor of a Binary Tree
224. Basic Calculator
268. Missing Number
240. Search a 2D Matrix II
289. Game of Life
208. Implement Trie (Prefix Tree)
230. Kth Smallest Element in a BST
227. Basic Calculator II
218. The Skyline Problem
215. Kth Largest Element in an Array
217. Contains Duplicate
150. Evaluate Reverse Polish Notation
172. Factorial Trailing Zeroes
202. Happy Number
166. Fraction to Recurring Decimal
191. Number of 1 Bits
190. Reverse Bits
148. Sort List
146. LRU Cache
128. Longest Consecutive Sequence
125. Valid Palindrome
171. Excel Sheet Column Number
134. Gas Station
169. Majority Element
42. Trapping Rain Water
76. Minimum Window Substring
703. Kth Largest Element in a Stream
49. Group Anagrams
55. Jump Game
56. Merge Intervals
48. Rotate Image
119. Pascal's Triangle II
118. Pascal's Triangle
28. Implement strStr()
19. Remove Nth Node From End of List
41. First Missing Positive
26. Remove Duplicates from Sorted Array
8. String to Integer (atoi)
14. Longest Common Prefix
13. Roman to Integer
12. Integer to Roman
983. Minimum Cost For Tickets
181. Employees Earning More Than Their Managers
178. Rank Scores
177. Nth Highest Salary
176. Second Highest Salary
175. Combine Two Tables
7. Reverse Integer
4. Median of Two Sorted Arrays
205. Isomorphic Strings
149. Max Points on a Line
730. Count Different Palindromic Subsequences
914. X of a Kind in a Deck of Cards
433. Minimum Genetic Mutation
501. Find Mode in Binary Search Tree
334. Increasing Triplet Subsequence
454. 4Sum II
66. Plus One
18. 4Sum
29. Divide Two Integers
714. Best Time to Buy and Sell Stock with Transaction Fee
495. Teemo Attacking
499. Word Count (Map Reduce)
430. Flatten a Multilevel Doubly Linked List
869. Reordered Power of 2
525. Contiguous Array
982. Triples with Bitwise AND Equal To Zero
54. Spiral Matrix
35. Search Insert Position
9.3 站队问题
9.2 方格移动
13.2 赛马
13.1 方格涂色
8.5 比较两数
8.3 交换两数
Bit Manipulation
389. Find the Difference
260. Single Number III
7.14 最大二叉搜索子树
7.11. 折纸问题
958. Check Completeness of a Binary Tree
543. Diameter of Binary Tree
333. Largest BST Subtree
449. Serialize and Deserialize BST
523. Continuous Subarray Sum
655. Print Binary Tree
297. Serialize and Deserialize Binary Tree
474. Ones and Zeroes
416. Partition Equal Subset Sum
12.9 最优编辑
12.8 01 背包问题
926. Flip String to Monotone Increasing
1143. Longest Common Subsequence
814. Binary Tree Pruning
812. Largest Triangle Area
36. Valid Sudoku
813. Largest Sum of Averages
815. Bus Routes
5.15 单链表相交判断
6.6 最左原位
222. Count Complete Tree Nodes
50. Pow(x, n)
34. Find First and Last Position of Element in Sorted Array
162. Find Peak Element
5.14 有环单链表相交判断
160. Intersection of Two Linked Lists
138. Copy List with Random Pointer
5.6 打印两个链表的公共值
86. Partition List
25. Reverse Nodes in k-Group
219. Insert Node in Sorted Linked List
708. Insert into a Cyclic Sorted List
4.9 数组变树练习题
239. Sliding Window Maximum
4.6 两栈排序
4.5 递归实现栈反转
232. Implement Queue using Stacks
225. Implement Stack using Queues
189. Rotate Array
572. Subtree of Another Tree
796. Rotate String
242. Valid Anagram
151. Reverse Words in a String
164. Maximum Gap
1031. Maximum Sum of Two Non-Overlapping Subarrays
132. Palindrome Partitioning II
131. Palindrome Partitioning
152. Maximum Product Subarray
123. Best Time to Buy and Sell Stock III
122. Best Time to Buy and Sell Stock II
95. Unique Binary Search Trees II
121. Best Time to Buy and Sell Stock
96. Unique Binary Search Trees
87. Scramble String
85. Maximal Rectangle
581. Shortest Unsorted Continuous Subarray
32. Longest Valid Parentheses
89. Gray Code
472. Concatenated Words
79. Word Search
60. Permutation Sequence
52. N-Queens II
44. Wildcard Matching
37. Sudoku Solver
77. Combinations
503. Next Greater Element II
496. Next Greater Element I
1263. Minimum Moves to Move a Box to Their Target Location
140. Word Break II
139. Word Break
213. House Robber II
90. Subsets II
47. Permutations II
20. Valid Parentheses
137. Single Number II
136. Single Number
154. Find Minimum in Rotated Sorted Array II
179. Largest Number
38. Count and Say
23. Merge k Sorted Lists
46. Permutations
74. Search a 2D Matrix
40. Combination Sum II
39. Combination Sum
216. Combination Sum III
33. Search in Rotated Sorted Array
75. Sort Colors
15. 3Sum

567. Permutation in String
443. String Compression
706. Design HashMap
11. Container With Most Water
473. Matchsticks to Square
394. Decode String
337. House Robber III
329. Longest Increasing Path in a Matrix
129. Sum Root to Leaf Numbers
124. Binary Tree Maximum Path Sum
117. Populating Next Right Pointers in Each Node II
116. Populating Next Right Pointers in Each Node
114. Flatten Binary Tree to Linked List
106. Construct Binary Tree from Inorder and Postorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal
Sort Algorithms

99. Recover Binary Search Tree
897. Increasing Order Search Tree
872. Leaf-Similar Trees
733. Flood Fill
110. Balanced Binary Tree
437. Path Sum III
257. Binary Tree Paths
113. Path Sum II
112. Path Sum
863. All Nodes Distance K in Binary Tree
Top K
109. Convert Sorted List to Binary Search Tree
108. Convert Sorted Array to Binary Search Tree
100. Same Tree
787. Cheapest Flights Within K Stops
73. Set Matrix Zeroes
72. Edit Distance
70. Climbing Stairs
704. Binary Search
700. Search in a Binary Search Tree
994. Rotting Oranges
993. Cousins in Binary Tree
785. Is Graph Bipartite?
559. Maximum Depth of N-ary Tree
429. N-ary Tree Level Order Traversal

155. Min Stack
752. Open the Lock
743. Network Delay Time
690. Employee Importance
542. 01 Matrix
133. Clone Graph
513. Find Bottom Left Tree Value
513. Find Bottom Left Tree Value
301. Remove Invalid Parentheses
310. Minimum Height Trees
210. Course Schedule II
207. Course Schedule
200. Number of Islands
199. Binary Tree Right Side View
130. Surrounded Regions
639. Decode Ways II
111. Minimum Depth of Binary Tree
91. Decode Ways
980. Unique Paths III
64. Minimum Path Sum
63. Unique Paths II
322. Coin Change
62. Unique Paths
5. Longest Palindromic Substring
1.4 两串旋转问题
107. Binary Tree Level Order Traversal II
103. Binary Tree Zigzag Level Order Traversal
12.4 台阶问题
212. Word Search II

12.2 找零钱
1155. Number of Dice Rolls With Target Sum
417. Pacific Atlantic Water Flow
XGBoost Parameter Tuning
Machine Learning Library
51. N-Queens
78. Subsets
94. Binary Tree Inorder Traversal
145. Binary Tree Postorder Traversal
144. Binary Tree Preorder Traversal
98. Validate Binary Search Tree
69. Sqrt(x)
88. Merge Sorted Array
633. Sum of Square Numbers
104. Maximum Depth of Binary Tree
7.5 二叉树分层打印
279. Perfect Squares
890. Find and Replace Pattern
198. House Robber
Exploratory Data Analysis
153. Find Minimum in Rotated Sorted Array
10. Regular Expression Matching
204. Count Primes
563. Binary Tree Tilt
17. Letter Combinations of a Phone Number
284. Peeking Iterator
Learn Storm From Scratch
300. Longest Increasing Subsequence
670. Maximum Swap
22. Generate Parentheses
900. RLE Iterator
332. Reconstruct Itinerary
380. Insert Delete GetRandom O(1)
067. 机器人的运动范围
066. 矩阵中的路径
065. 滑动窗口的最大值
064. 数据流中的中位数
063. 二叉搜索树的第K个结点
062. 序列化二叉树
061. 按之字形顺序打印二叉树
060. 把二叉树打印成多行
059. 对称的二叉树
102. Binary Tree Level Order Traversal
058. 二叉树的下一个结点
057. 删除链表中重复的结点
056. 链表中环的入口结点
055. 字符流中第一个不重复的字符
054. 表示数值的字符串
053. 正则表达式匹配
052. 构建乘积数组
051. 数组中重复的数字
049. 把字符串传换成整数
046. 求 1+2+···+n
045. 圆圈中最后剩下的数字
Term Frequency Inverse Document Frequency
044. 扑克牌顺子
Named Entity Recognition
043. n 个骰子的点数
042a. 左旋转字符串
042. 翻转单词序列
041a. 和为 S 的连续整数序列
041. 和为 s 的两个数字 VS 和为 s 的连续整数序列
040. 数组中只出现一次的数字
Tree
039a. 平衡二叉树
039. 二叉树的深度
038. 数字在排序数组中出现的次数
037. 两个链表的第一个公共结点
036. 数组中的逆序对
035. 第一个只出现一次的字符
034. 丑数
Permutation
Natural Language Processing
Learn Spark From Scratch
033. 把数组排成最小的数
032. 整数中1出现的次数
84. Largest Rectangle in Histogram
031. 连续子数组的最大和
030. 最小的 K 个数
029. 数组中出现次数超过一半的数字
028. 字符串排列
027. 二叉搜索树与双向链表
026. 复杂链表的复制
025. 二叉树中和为某一值的路径
024. 从上往下打印二叉树
023. 从上往下打印二叉树
022. 栈的压入弹出序列
021. 包含 min 函数的栈
020. 顺时针打印矩阵
019. 二叉树的镜像
018. 树的子结构
017. 合并两个排序的链表
016. 反转链表
015. 链表中倒数第K个结点
014. 调整数组顺序使奇数位于偶数前面

12. 打印 1 到最大的 n 位数

009. 斐波那契数列
008. 旋转数组的最小数字

795. Number of Subarrays with Bounded Maximum
Binary Search

002. 实现 Singleton 模式

21. Merge Two Sorted Lists
Matrix Multiplication
101. Symmetric Tree
Outline of Coding
OJ 编程总结
235. Lowest Common Ancestor of a Binary Search Tree
3. Longest Substring Without Repeating Characters
238. Product of Array Except Self
287. Find the Duplicate Number
1. Two Sum

## Competitions (7)

Web Traffic Time Series Forecasting
Competitions Reproduction
2019 年搜狐算法大赛整理

Kaggle 入门一步一步记录

## Computer Vision (3)

Railway Detection
Keras YOLOv3
Single Shot MultiBox Detector

## Convex Optimization (1)

Lagrange Multiplier

## DFS (41)

472. Concatenated Words
140. Word Break II
39. Combination Sum
473. Matchsticks to Square
394. Decode String
337. House Robber III
329. Longest Increasing Path in a Matrix
116. Populating Next Right Pointers in Each Node
114. Flatten Binary Tree to Linked List
106. Construct Binary Tree from Inorder and Postorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal
99. Recover Binary Search Tree
897. Increasing Order Search Tree
872. Leaf-Similar Trees
733. Flood Fill
437. Path Sum III
112. Path Sum
108. Convert Sorted Array to Binary Search Tree
787. Cheapest Flights Within K Stops
785. Is Graph Bipartite?
559. Maximum Depth of N-ary Tree
429. N-ary Tree Level Order Traversal
752. Open the Lock
743. Network Delay Time
690. Employee Importance
542. 01 Matrix
133. Clone Graph
301. Remove Invalid Parentheses
210. Course Schedule II
207. Course Schedule
130. Surrounded Regions
111. Minimum Depth of Binary Tree
980. Unique Paths III
212. Word Search II

417. Pacific Atlantic Water Flow
78. Subsets
94. Binary Tree Inorder Traversal
144. Binary Tree Preorder Traversal
17. Letter Combinations of a Phone Number
332. Reconstruct Itinerary

## DP (43)

1105. Filling Bookcase Shelves
1301. Number of Paths with Max Score
1147. Longest Chunked Palindrome Decomposition
664. Strange Printer
264. Ugly Number II
312. Burst Balloons
494. Target Sum
338. Counting Bits
309. Best Time to Buy and Sell Stock with Cooldown
221. Maximal Square
983. Minimum Cost For Tickets
730. Count Different Palindromic Subsequences
714. Best Time to Buy and Sell Stock with Transaction Fee
474. Ones and Zeroes
416. Partition Equal Subset Sum
12.9 最优编辑
926. Flip String to Monotone Increasing
1143. Longest Common Subsequence
813. Largest Sum of Averages
132. Palindrome Partitioning II
152. Maximum Product Subarray
123. Best Time to Buy and Sell Stock III
95. Unique Binary Search Trees II
96. Unique Binary Search Trees
87. Scramble String
32. Longest Valid Parentheses
139. Word Break
213. House Robber II
787. Cheapest Flights Within K Stops
72. Edit Distance
639. Decode Ways II
91. Decode Ways
980. Unique Paths III
63. Unique Paths II
322. Coin Change
62. Unique Paths
5. Longest Palindromic Substring
1155. Number of Dice Rolls With Target Sum
417. Pacific Atlantic Water Flow
279. Perfect Squares
198. House Robber
10. Regular Expression Matching
300. Longest Increasing Subsequence

## Data Structures (10)

Hash Table
Stack and Queue
String
Greedy Algorithms
Branch And Bound
Outline Of Data Structure And Algorithms
Backtracking
Recursion
Depth-First Search

## Deep Learning (33)

Graph Embedding
Graph Convolutional Network
You Only Look Once
Data Augmentation
LeNet
Batch Normalization
Fully Connected Layer
Weights Initialization in Deep Learning
Fast RCNN
Region-based CNN
Pretrained Network
You Only Look Once
You Only Look Once
Smooth $L_1$
Faster RCNN
Semantic Segmentation
Convolutional Neural Network
Triplet Loss
Normalization
You Only Look Once
Non-Max Suppression
Recurrent Neural Networks
Long Short Term Memory networks
K-Nearest Neighbers
PyTorch Usage Records
Pooling Layers
Bounding Box Regression
Optimizers
Object Detection
Very Deep Convolutional Networks

TensorFlow
Dropout

## Design (3)

146. LRU Cache
284. Peeking Iterator
380. Insert Delete GetRandom O(1)

## Dimension Reduction (1)

Principal Components Analysis

Docker 使用记录

## Easy (86)

876. Middle of the Linked List
53. Maximum Subarray
844. Backspace String Compare
195. Tenth Line
193. Valid Phone Numbers
867. Transpose Matrix
985. Sum of Even Numbers After Queries
1184. Distance Between Bus Stops
1290. Convert Binary Number in a Linked List to Integer
263. Ugly Number
58. Length of Last Word
83. Remove Duplicates from Sorted List
9. Palindrome Number
27. Remove Element
448. Find All Numbers Disappeared in an Array
617. Merge Two Binary Trees
226. Invert Binary Tree
387. First Unique Character in a String
371. Sum of Two Integers
412. Fizz Buzz
344. Reverse String
350. Intersection of Two Arrays II
349. Intersection of Two Arrays
326. Power of Three
283. Move Zeroes
268. Missing Number
217. Contains Duplicate
172. Factorial Trailing Zeroes
202. Happy Number
191. Number of 1 Bits
190. Reverse Bits
125. Valid Palindrome
169. Majority Element
703. Kth Largest Element in a Stream
119. Pascal's Triangle II
118. Pascal's Triangle
28. Implement strStr()
26. Remove Duplicates from Sorted Array
14. Longest Common Prefix
13. Roman to Integer
181. Employees Earning More Than Their Managers
176. Second Highest Salary
175. Combine Two Tables
7. Reverse Integer
205. Isomorphic Strings
914. X of a Kind in a Deck of Cards
501. Find Mode in Binary Search Tree
66. Plus One
35. Search Insert Position
389. Find the Difference
543. Diameter of Binary Tree
812. Largest Triangle Area
160. Intersection of Two Linked Lists
232. Implement Queue using Stacks
225. Implement Stack using Queues
189. Rotate Array
572. Subtree of Another Tree
796. Rotate String
242. Valid Anagram
122. Best Time to Buy and Sell Stock II
121. Best Time to Buy and Sell Stock
581. Shortest Unsorted Continuous Subarray
20. Valid Parentheses
136. Single Number
38. Count and Say
443. String Compression
706. Design HashMap
108. Convert Sorted Array to Binary Search Tree
155. Min Stack
690. Employee Importance
111. Minimum Depth of Binary Tree
107. Binary Tree Level Order Traversal II
69. Sqrt(x)
88. Merge Sorted Array
633. Sum of Square Numbers
104. Maximum Depth of Binary Tree
198. House Robber
204. Count Primes
563. Binary Tree Tilt
21. Merge Two Sorted Lists
1. Two Sum

LightGBM
Random Forest

## Feature Engineering (3)

Training Models With Python
Workflow Of Model Training
Feature Engineering Using Python

## Geometry (3)

Line Detection

Camera Calibration

## Graph (2)

417. Pacific Atlantic Water Flow
332. Reconstruct Itinerary

## Graph Model (2)

Graph Embedding
Graph Convolutional Network
787. Cheapest Flights Within K Stops

## Greedy (10)

1147. Longest Chunked Palindrome Decomposition
45. Jump Game II
406. Queue Reconstruction by Height
134. Gas Station
55. Jump Game
334. Increasing Triplet Subsequence
122. Best Time to Buy and Sell Stock II
5. Longest Palindromic Substring
890. Find and Replace Pattern

## Hard (49)

854. K-Similar Strings
1301. Number of Paths with Max Score
1147. Longest Chunked Palindrome Decomposition
664. Strange Printer
391. Perfect Rectangle
45. Jump Game II
30. Substring with Concatenation of All Words
312. Burst Balloons
315. Count of Smaller Numbers After Self
295. Find Median from Data Stream
224. Basic Calculator
218. The Skyline Problem
128. Longest Consecutive Sequence
42. Trapping Rain Water
76. Minimum Window Substring
41. First Missing Positive
4. Median of Two Sorted Arrays
149. Max Points on a Line
730. Count Different Palindromic Subsequences
982. Triples with Bitwise AND Equal To Zero
297. Serialize and Deserialize Binary Tree
25. Reverse Nodes in k-Group
239. Sliding Window Maximum
164. Maximum Gap
132. Palindrome Partitioning II
123. Best Time to Buy and Sell Stock III
87. Scramble String
85. Maximal Rectangle
32. Longest Valid Parentheses
472. Concatenated Words
52. N-Queens II
44. Wildcard Matching
37. Sudoku Solver
1263. Minimum Moves to Move a Box to Their Target Location
140. Word Break II
154. Find Minimum in Rotated Sorted Array II
23. Merge k Sorted Lists
329. Longest Increasing Path in a Matrix
124. Binary Tree Maximum Path Sum
99. Recover Binary Search Tree
72. Edit Distance
639. Decode Ways II
980. Unique Paths III
212. Word Search II
51. N-Queens
145. Binary Tree Postorder Traversal
10. Regular Expression Matching
84. Largest Rectangle in Histogram

## Hash Table (22)

391. Perfect Rectangle
508. Most Frequent Subtree Sum
438. Find All Anagrams in a String
560. Subarray Sum Equals K
387. First Unique Character in a String
347. Top K Frequent Elements
350. Intersection of Two Arrays II
349. Intersection of Two Arrays
217. Contains Duplicate
202. Happy Number
166. Fraction to Recurring Decimal
146. LRU Cache
49. Group Anagrams
205. Isomorphic Strings
149. Max Points on a Line
869. Reordered Power of 2
36. Valid Sudoku
136. Single Number
567. Permutation in String
706. Design HashMap
3. Longest Substring Without Repeating Characters
1. Two Sum

## Heap (7)

378. Kth Smallest Element in a Sorted Matrix
347. Top K Frequent Elements
295. Find Median from Data Stream
218. The Skyline Problem
215. Kth Largest Element in an Array
703. Kth Largest Element in a Stream
23. Merge k Sorted Lists

SQL
Hive Level Up

## Image Classification (2)

LeNet
Very Deep Convolutional Networks

## Information Theory (2)

Information Entropy
Information Theory

## Kaggle (1)

Web Traffic Time Series Forecasting

## LeetCode (328)

876. Middle of the Linked List
53. Maximum Subarray
1105. Filling Bookcase Shelves
844. Backspace String Compare
854. K-Similar Strings
1171. Remove Zero Sum Consecutive Nodes from Linked List
195. Tenth Line
194. Transpose File
193. Valid Phone Numbers
192. Word Frequency
867. Transpose Matrix
1302. Deepest Leaves Sum
1301. Number of Paths with Max Score
985. Sum of Even Numbers After Queries
398. Random Pick Index
1184. Distance Between Bus Stops
1147. Longest Chunked Palindrome Decomposition
664. Strange Printer
391. Perfect Rectangle
1290. Convert Binary Number in a Linked List to Integer
3278. Catch That Cow
264. Ugly Number II
263. Ugly Number
508. Most Frequent Subtree Sum
45. Jump Game II
58. Length of Last Word
43. Multiply Strings
30. Substring with Concatenation of All Words
83. Remove Duplicates from Sorted List
9. Palindrome Number
24. Swap Nodes in Pairs
27. Remove Element
16. 3Sum Closest
6. ZigZag Conversion
312. Burst Balloons
406. Queue Reconstruction by Height
438. Find All Anagrams in a String
647. Palindromic Substrings
494. Target Sum
560. Subarray Sum Equals K
448. Find All Numbers Disappeared in an Array
617. Merge Two Binary Trees
739. Daily Temperatures
338. Counting Bits
31. Next Permutation
226. Invert Binary Tree
309. Best Time to Buy and Sell Stock with Cooldown
221. Maximal Square
395. Longest Substring with At Least K Repeating Characters
387. First Unique Character in a String
371. Sum of Two Integers
378. Kth Smallest Element in a Sorted Matrix
412. Fizz Buzz
384. Shuffle an Array
344. Reverse String
341. Flatten Nested List Iterator
347. Top K Frequent Elements
350. Intersection of Two Arrays II
349. Intersection of Two Arrays
315. Count of Smaller Numbers After Self
324. Wiggle Sort II
326. Power of Three
295. Find Median from Data Stream
283. Move Zeroes
236. Lowest Common Ancestor of a Binary Tree
224. Basic Calculator
268. Missing Number
240. Search a 2D Matrix II
289. Game of Life
208. Implement Trie (Prefix Tree)
230. Kth Smallest Element in a BST
227. Basic Calculator II
218. The Skyline Problem
215. Kth Largest Element in an Array
217. Contains Duplicate
150. Evaluate Reverse Polish Notation
172. Factorial Trailing Zeroes
202. Happy Number
166. Fraction to Recurring Decimal
191. Number of 1 Bits
190. Reverse Bits
148. Sort List
146. LRU Cache
128. Longest Consecutive Sequence
125. Valid Palindrome
171. Excel Sheet Column Number
134. Gas Station
169. Majority Element
42. Trapping Rain Water
76. Minimum Window Substring
703. Kth Largest Element in a Stream
49. Group Anagrams
55. Jump Game
56. Merge Intervals
48. Rotate Image
119. Pascal's Triangle II
118. Pascal's Triangle
28. Implement strStr()
19. Remove Nth Node From End of List
41. First Missing Positive
26. Remove Duplicates from Sorted Array
8. String to Integer (atoi)
14. Longest Common Prefix
13. Roman to Integer
12. Integer to Roman
983. Minimum Cost For Tickets
181. Employees Earning More Than Their Managers
178. Rank Scores
177. Nth Highest Salary
176. Second Highest Salary
175. Combine Two Tables
7. Reverse Integer
4. Median of Two Sorted Arrays
205. Isomorphic Strings
149. Max Points on a Line
730. Count Different Palindromic Subsequences
914. X of a Kind in a Deck of Cards
433. Minimum Genetic Mutation
501. Find Mode in Binary Search Tree
334. Increasing Triplet Subsequence
454. 4Sum II
66. Plus One
18. 4Sum
29. Divide Two Integers
714. Best Time to Buy and Sell Stock with Transaction Fee
495. Teemo Attacking
430. Flatten a Multilevel Doubly Linked List
869. Reordered Power of 2
525. Contiguous Array
982. Triples with Bitwise AND Equal To Zero
54. Spiral Matrix
35. Search Insert Position
Bit Manipulation
389. Find the Difference
260. Single Number III
958. Check Completeness of a Binary Tree
543. Diameter of Binary Tree
333. Largest BST Subtree
449. Serialize and Deserialize BST
523. Continuous Subarray Sum
655. Print Binary Tree
297. Serialize and Deserialize Binary Tree
474. Ones and Zeroes
416. Partition Equal Subset Sum
926. Flip String to Monotone Increasing
1143. Longest Common Subsequence
814. Binary Tree Pruning
812. Largest Triangle Area
36. Valid Sudoku
813. Largest Sum of Averages
815. Bus Routes
222. Count Complete Tree Nodes
50. Pow(x, n)
34. Find First and Last Position of Element in Sorted Array
162. Find Peak Element
160. Intersection of Two Linked Lists
138. Copy List with Random Pointer
86. Partition List
25. Reverse Nodes in k-Group
708. Insert into a Cyclic Sorted List
239. Sliding Window Maximum
232. Implement Queue using Stacks
225. Implement Stack using Queues
189. Rotate Array
572. Subtree of Another Tree
796. Rotate String
242. Valid Anagram
151. Reverse Words in a String
164. Maximum Gap
1031. Maximum Sum of Two Non-Overlapping Subarrays
132. Palindrome Partitioning II
131. Palindrome Partitioning
152. Maximum Product Subarray
123. Best Time to Buy and Sell Stock III
122. Best Time to Buy and Sell Stock II
95. Unique Binary Search Trees II
121. Best Time to Buy and Sell Stock
96. Unique Binary Search Trees
87. Scramble String
85. Maximal Rectangle
581. Shortest Unsorted Continuous Subarray
32. Longest Valid Parentheses
89. Gray Code
472. Concatenated Words
79. Word Search
60. Permutation Sequence
52. N-Queens II
44. Wildcard Matching
37. Sudoku Solver
77. Combinations
503. Next Greater Element II
496. Next Greater Element I
1263. Minimum Moves to Move a Box to Their Target Location
140. Word Break II
139. Word Break
213. House Robber II
90. Subsets II
47. Permutations II
20. Valid Parentheses
137. Single Number II
136. Single Number
154. Find Minimum in Rotated Sorted Array II
179. Largest Number
38. Count and Say
23. Merge k Sorted Lists
46. Permutations
74. Search a 2D Matrix
40. Combination Sum II
39. Combination Sum
216. Combination Sum III
33. Search in Rotated Sorted Array
75. Sort Colors
15. 3Sum
567. Permutation in String
443. String Compression
706. Design HashMap
11. Container With Most Water
473. Matchsticks to Square
394. Decode String
337. House Robber III
329. Longest Increasing Path in a Matrix
129. Sum Root to Leaf Numbers
124. Binary Tree Maximum Path Sum
117. Populating Next Right Pointers in Each Node II
116. Populating Next Right Pointers in Each Node
114. Flatten Binary Tree to Linked List
106. Construct Binary Tree from Inorder and Postorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal

99. Recover Binary Search Tree
897. Increasing Order Search Tree
872. Leaf-Similar Trees
733. Flood Fill
110. Balanced Binary Tree
437. Path Sum III
257. Binary Tree Paths
113. Path Sum II
112. Path Sum
863. All Nodes Distance K in Binary Tree
109. Convert Sorted List to Binary Search Tree
108. Convert Sorted Array to Binary Search Tree
100. Same Tree
787. Cheapest Flights Within K Stops
73. Set Matrix Zeroes
72. Edit Distance
70. Climbing Stairs
704. Binary Search
700. Search in a Binary Search Tree
994. Rotting Oranges
993. Cousins in Binary Tree
785. Is Graph Bipartite?
559. Maximum Depth of N-ary Tree
429. N-ary Tree Level Order Traversal
155. Min Stack
752. Open the Lock
743. Network Delay Time
690. Employee Importance
542. 01 Matrix
133. Clone Graph
513. Find Bottom Left Tree Value
513. Find Bottom Left Tree Value
301. Remove Invalid Parentheses
310. Minimum Height Trees
210. Course Schedule II
207. Course Schedule
200. Number of Islands
199. Binary Tree Right Side View
130. Surrounded Regions
639. Decode Ways II
111. Minimum Depth of Binary Tree
91. Decode Ways
980. Unique Paths III
64. Minimum Path Sum
63. Unique Paths II
322. Coin Change
62. Unique Paths
5. Longest Palindromic Substring
107. Binary Tree Level Order Traversal II
103. Binary Tree Zigzag Level Order Traversal
212. Word Search II
1155. Number of Dice Rolls With Target Sum
417. Pacific Atlantic Water Flow
51. N-Queens
78. Subsets
94. Binary Tree Inorder Traversal
145. Binary Tree Postorder Traversal
144. Binary Tree Preorder Traversal
98. Validate Binary Search Tree
69. Sqrt(x)
88. Merge Sorted Array
633. Sum of Square Numbers
104. Maximum Depth of Binary Tree
279. Perfect Squares
890. Find and Replace Pattern
198. House Robber
153. Find Minimum in Rotated Sorted Array
10. Regular Expression Matching
204. Count Primes
563. Binary Tree Tilt
17. Letter Combinations of a Phone Number
284. Peeking Iterator
300. Longest Increasing Subsequence
22. Generate Parentheses
900. RLE Iterator
332. Reconstruct Itinerary
380. Insert Delete GetRandom O(1)
102. Binary Tree Level Order Traversal
84. Largest Rectangle in Histogram
21. Merge Two Sorted Lists
101. Symmetric Tree
235. Lowest Common Ancestor of a Binary Search Tree
3. Longest Substring Without Repeating Characters
238. Product of Array Except Self
287. Find the Duplicate Number
1. Two Sum

## Line Sweep (2)

391. Perfect Rectangle
218. The Skyline Problem

## Linear Algebra (2)

Linear Algebra
Norm

876. Middle of the Linked List
1171. Remove Zero Sum Consecutive Nodes from Linked List
1290. Convert Binary Number in a Linked List to Integer
30. Substring with Concatenation of All Words
83. Remove Duplicates from Sorted List
24. Swap Nodes in Pairs
148. Sort List
146. LRU Cache
19. Remove Nth Node From End of List
430. Flatten a Multilevel Doubly Linked List
5.14 有环单链表相交判断
160. Intersection of Two Linked Lists
138. Copy List with Random Pointer
5.6 打印两个链表的公共值
86. Partition List
25. Reverse Nodes in k-Group
219. Insert Node in Sorted Linked List
708. Insert into a Cyclic Sorted List
23. Merge k Sorted Lists
21. Merge Two Sorted Lists
287. Find the Duplicate Number

## LintCode (3)

499. Word Count (Map Reduce)
219. Insert Node in Sorted Linked List
708. Insert into a Cyclic Sorted List

Linux 使用记录

Triplet Loss

## Machine Learning (124)

Hyperparameter Optimization/Tuning
DBSCAN
Clustering
Sample Selection
Clustering Metrics
Sklearn

Model Metrics
Spark 高级数据分析
Feature Extraction
The Exponential Family
Generalized Linear Model
Line Detection
VC Dimension
Kernel Method
The Glory and the Dream
Non-negative Matrix Factorization
Hierarchical Agglomerative Clustering
Distance Estimation
Convex Optimization

Camera Calibration
Maximum A Posteriori Estimation
Machine Learning Projects
Stacking
Interview Questions
Steepest Descent
LightGBM
Softmax Regression
Resampling
Resampling For Imbalanced Dataset

Factorization Machines
Deep Factorization Machines
Model Selection
Exploratory Data Analysis
O2O 优惠券预测使用
Self Organizing Map
Gaussian Mixture Model
Expectation Maximization
A/B Test
Hyperparameter Optimization

Outline of Dimension Reduction
Outline Of Unsupervised Learning
Feature Extraction

Outlier Detection
Distance Metrics
Forward Stagewise Algorithm
Boosting Tree
Types of Model
Iterative Dichotomiser 3
Decision Stump
Classification and Regression Tree
C4.5
Perceptron
Overfitting and Underfitting
Norm
Regularization
K-Means
Bayesian Linear Regression
Review of Machine Learning Algorithms
050. 最近公共祖先
048. 不能被继承的类
047. 不用加减乘除做加法
Interview Questions
Maximum Likelihood Estimation
Naive Bayes
Conditional Random Field
Activation Functions
Recommendation System
Job Requirements
Classification Metrics
Principal Components Analysis

Data Leakage
Outline Of Machine Learning
Optimizers
Click Models
Workflow Of Applying Machine Learning Algorithms Offline To Online
Model Optimization
Dynamic Programming
Interview

Competitions Workflow Of Classification And Regression
Ensemble Learning
Ranking Algorithms
Single Shot Multibox Detector
Bias and Variance
Ridge and Lasso Regression
Polynomial Regression
Locally Weighted Linear Regression
Support Vector Machines
Exploratory Data Analysis
Human Activity Recognition
Applied Machine Learning Summary
Outline of Applied Machine Learning Algorithms
Random Forest
Regression Metrics
Data Preprocessing
Field-aware Factorization Machines
XGBoost
Neural Network
Model Ensemble
Feature Selection
Decision Tree
Linear Discriminant Analysis
Kaggle 入门一步一步记录
Linear Regression
Feature Engineering
Random Features for Large-Scale Kernel Machines
Logistic Regression

## MapReduce (5)

Word Count
MapReduce 实现 K-Means
499. Word Count (Map Reduce)
Top K

## Math (11)

264. Ugly Number II
263. Ugly Number
326. Power of Three
172. Factorial Trailing Zeroes
7. Reverse Integer
149. Max Points on a Line
29. Divide Two Integers
523. Continuous Subarray Sum
812. Largest Triangle Area
69. Sqrt(x)
204. Count Primes

## Mathematics (15)

Differentiation
Quasi-Newton's Method
Linear Algebra
Lagrange Multiplier
Laplace Distribution
Basic Computing
Preliminaries Knowledge of Probability Theory
Taylor Series
Normal Distribution
Monte Carlo Method
Singular Value Decomposition
Matrix Factorization
Matrix
Newton's Method

## Medium (146)

1105. Filling Bookcase Shelves
1171. Remove Zero Sum Consecutive Nodes from Linked List
194. Transpose File
192. Word Frequency
1302. Deepest Leaves Sum
398. Random Pick Index
264. Ugly Number II
508. Most Frequent Subtree Sum
43. Multiply Strings
24. Swap Nodes in Pairs
16. 3Sum Closest
6. ZigZag Conversion
406. Queue Reconstruction by Height
438. Find All Anagrams in a String
494. Target Sum
560. Subarray Sum Equals K
739. Daily Temperatures
338. Counting Bits
31. Next Permutation
309. Best Time to Buy and Sell Stock with Cooldown
221. Maximal Square
395. Longest Substring with At Least K Repeating Characters
378. Kth Smallest Element in a Sorted Matrix
384. Shuffle an Array
341. Flatten Nested List Iterator
347. Top K Frequent Elements
324. Wiggle Sort II
236. Lowest Common Ancestor of a Binary Tree
240. Search a 2D Matrix II
289. Game of Life
208. Implement Trie (Prefix Tree)
230. Kth Smallest Element in a BST
227. Basic Calculator II
215. Kth Largest Element in an Array
150. Evaluate Reverse Polish Notation
166. Fraction to Recurring Decimal
148. Sort List
146. LRU Cache
134. Gas Station
49. Group Anagrams
55. Jump Game
56. Merge Intervals
48. Rotate Image
19. Remove Nth Node From End of List
8. String to Integer (atoi)
12. Integer to Roman
983. Minimum Cost For Tickets
178. Rank Scores
177. Nth Highest Salary
433. Minimum Genetic Mutation
334. Increasing Triplet Subsequence
454. 4Sum II
18. 4Sum
29. Divide Two Integers
714. Best Time to Buy and Sell Stock with Transaction Fee
495. Teemo Attacking
430. Flatten a Multilevel Doubly Linked List
869. Reordered Power of 2
260. Single Number III
958. Check Completeness of a Binary Tree
449. Serialize and Deserialize BST
523. Continuous Subarray Sum
655. Print Binary Tree
474. Ones and Zeroes
416. Partition Equal Subset Sum
926. Flip String to Monotone Increasing
1143. Longest Common Subsequence
814. Binary Tree Pruning
36. Valid Sudoku
813. Largest Sum of Averages
222. Count Complete Tree Nodes
50. Pow(x, n)
34. Find First and Last Position of Element in Sorted Array
162. Find Peak Element
138. Copy List with Random Pointer
86. Partition List
708. Insert into a Cyclic Sorted List
151. Reverse Words in a String
1031. Maximum Sum of Two Non-Overlapping Subarrays
131. Palindrome Partitioning
152. Maximum Product Subarray
95. Unique Binary Search Trees II
96. Unique Binary Search Trees
89. Gray Code
79. Word Search
60. Permutation Sequence
77. Combinations
503. Next Greater Element II
139. Word Break
213. House Robber II
90. Subsets II
47. Permutations II
137. Single Number II
179. Largest Number
46. Permutations
74. Search a 2D Matrix
40. Combination Sum II
39. Combination Sum
216. Combination Sum III
33. Search in Rotated Sorted Array
75. Sort Colors
15. 3Sum
567. Permutation in String
11. Container With Most Water
473. Matchsticks to Square
394. Decode String
337. House Robber III
117. Populating Next Right Pointers in Each Node II
116. Populating Next Right Pointers in Each Node
114. Flatten Binary Tree to Linked List
106. Construct Binary Tree from Inorder and Postorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal
73. Set Matrix Zeroes
310. Minimum Height Trees
130. Surrounded Regions
91. Decode Ways
64. Minimum Path Sum
63. Unique Paths II
322. Coin Change
62. Unique Paths
5. Longest Palindromic Substring
103. Binary Tree Zigzag Level Order Traversal
1155. Number of Dice Rolls With Target Sum
417. Pacific Atlantic Water Flow
144. Binary Tree Preorder Traversal
98. Validate Binary Search Tree
279. Perfect Squares
890. Find and Replace Pattern
153. Find Minimum in Rotated Sorted Array
17. Letter Combinations of a Phone Number
284. Peeking Iterator
300. Longest Increasing Subsequence
22. Generate Parentheses
900. RLE Iterator
332. Reconstruct Itinerary
380. Insert Delete GetRandom O(1)
102. Binary Tree Level Order Traversal
3. Longest Substring Without Repeating Characters
238. Product of Array Except Self

## Metrics (1)

Classification Metrics

Model Selection

Hamlet

Django
MySQL Level Up

9.3 站队问题
9.2 方格移动
13.2 赛马
13.1 方格涂色
8.5 比较两数
8.3 交换两数
7.14 最大二叉搜索子树
7.11. 折纸问题
12.9 最优编辑
12.8 01 背包问题
5.15 单链表相交判断
6.6 最左原位
5.14 有环单链表相交判断
5.6 打印两个链表的公共值
4.9 数组变树练习题
4.6 两栈排序
4.5 递归实现栈反转

1.4 两串旋转问题
12.4 台阶问题
12.2 找零钱
7.5 二叉树分层打印

## Object Detection (9)

You Only Look Once
Fast RCNN
Region-based CNN
You Only Look Once
You Only Look Once
Semantic Segmentation
You Only Look Once
Single Shot Multibox Detector
Object Detection

## Outline (5)

Essays
Projects
Outline Of Programming Skills
Outline of Algorithms

## Pandas (1)

Learn Pandas From Scratch

SA-SSD

## Probability Theory (3)

Laplace Distribution
Preliminaries Knowledge of Probability Theory
Normal Distribution

## Programming (8)

PyTorch
Scala
Anaconda
Outline Of Programming Skills
Jupyter 使用记录
Linux 使用记录
C++
Python 基础教程

## Psychology (4)

The Psychology of Judgment and Decision Making

## PyTorch (1)

PyTorch Usage Records

## Python (15)

Model Selection
Training Models With Python
Exploratory Data Analysis
Plotly
Sklearn
Feature Selection Using Python
Workflow Of Model Training
Feature Engineering Using Python
Matplotlib
Python Level Up
Learn Numpy From Scratch
Learn Seaborn From Scratch
Learn Pandas From Scratch
Jupyter 使用记录
Python 基础教程

## Queue (2)

239. Sliding Window Maximum
225. Implement Stack using Queues

## Recommendation System (1)

Recommendation System

## Recommender System (3)

Factorization Machines
Deep Factorization Machines
Field-aware Factorization Machines

## Recursion (3)

95. Unique Binary Search Trees II
87. Scramble String
89. Gray Code

Dropout

## SQL (5)

181. Employees Earning More Than Their Managers
178. Rank Scores
177. Nth Highest Salary
176. Second Highest Salary
175. Combine Two Tables

## Sampling (1)

Sample Selection
79. Word Search
1263. Minimum Moves to Move a Box to Their Target Location
417. Pacific Atlantic Water Flow

## Sliding Window (2)

567. Permutation in String
3. Longest Substring Without Repeating Characters

## Sort (7)

324. Wiggle Sort II
148. Sort List
56. Merge Intervals
164. Maximum Gap
581. Shortest Unsorted Continuous Subarray
179. Largest Number
Sort Algorithms

## Stack (11)

844. Backspace String Compare
739. Daily Temperatures
341. Flatten Nested List Iterator
224. Basic Calculator
227. Basic Calculator II
150. Evaluate Reverse Polish Notation
4.6 两栈排序
232. Implement Queue using Stacks
85. Maximal Rectangle
20. Valid Parentheses
155. Min Stack

## String (22)

58. Length of Last Word
43. Multiply Strings
30. Substring with Concatenation of All Words
6. ZigZag Conversion
224. Basic Calculator
227. Basic Calculator II
125. Valid Palindrome
76. Minimum Window Substring
28. Implement strStr()
8. String to Integer (atoi)
14. Longest Common Prefix
13. Roman to Integer
12. Integer to Roman
796. Rotate String
242. Valid Anagram
151. Reverse Words in a String
20. Valid Parentheses
38. Count and Say
443. String Compression
5. Longest Palindromic Substring
890. Find and Replace Pattern

## TODO (1)

41. First Missing Positive

TensorFlow

Mail Templates
topic
LaTex
Jekyll 搭建博客遇到的问题

## Tree (36)

1302. Deepest Leaves Sum
508. Most Frequent Subtree Sum
617. Merge Two Binary Trees
226. Invert Binary Tree
236. Lowest Common Ancestor of a Binary Tree
230. Kth Smallest Element in a BST
501. Find Mode in Binary Search Tree
7.14 最大二叉搜索子树
7.11. 折纸问题
958. Check Completeness of a Binary Tree
543. Diameter of Binary Tree
333. Largest BST Subtree
449. Serialize and Deserialize BST
655. Print Binary Tree
297. Serialize and Deserialize Binary Tree
814. Binary Tree Pruning
222. Count Complete Tree Nodes
572. Subtree of Another Tree
95. Unique Binary Search Trees II
124. Binary Tree Maximum Path Sum
106. Construct Binary Tree from Inorder and Postorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal
99. Recover Binary Search Tree
897. Increasing Order Search Tree
110. Balanced Binary Tree
437. Path Sum III
863. All Nodes Distance K in Binary Tree
100. Same Tree
94. Binary Tree Inorder Traversal
145. Binary Tree Postorder Traversal
144. Binary Tree Preorder Traversal
98. Validate Binary Search Tree
104. Maximum Depth of Binary Tree
563. Binary Tree Tilt
102. Binary Tree Level Order Traversal
101. Symmetric Tree

## Trie (2)

208. Implement Trie (Prefix Tree)
212. Word Search II

## Two Pointers (16)

30. Substring with Concatenation of All Words
27. Remove Element
16. 3Sum Closest
283. Move Zeroes
42. Trapping Rain Water
76. Minimum Window Substring
18. 4Sum
151. Reverse Words in a String
75. Sort Colors
15. 3Sum
567. Permutation in String
11. Container With Most Water
633. Sum of Square Numbers
3. Longest Substring Without Repeating Characters

## Union Find (1)

128. Longest Consecutive Sequence

## Unsupervised Learning (1)

Principal Components Analysis