README.md

Readme

Introduction

Hi, welcome to my leetcode "diary". I am currently trying to learn algorithm and solve algorithm problems. So this is the place where I put my thoughts and solutions to specific problems on leetcode. Feel free to leave a comment as well.

Table of contents

🌲 Tree Questions

• 👍 Binary Search Tree Traversal
  • 94 Binary Tree Inorder Traversal
  • 144 Binary Tree Preorder Traversal
  • 145 Binary Tree Postorder Traversal
• All sorts of tree problems
  • 700. Search in a Binary Search Tree
  • 671. Second Minimum Node In a Binary Tree
  • 637. Average of Levels in Binary Tree
  • 617. Merge Two Binary Trees
  • 606. Construct String from Binary Tree
  • 590. N-ary Tree Postorder Traversal
  • 589. N-ary Tree Preorder Traversal
  • 572. Subtree of Another Tree
  • 563. Binary Tree Tilt
  • 559. Maximum Depth of N-ary Tree
  • 543. Diameter of Binary Tree
  • 530. Minimum Absolute Difference in BST
  • 404. Sum of Left Leaves
  • 501. Find Mode in Binary Search Tree
  • 235. Lowest Common Ancestor of a Binary Search Tree
  • 257. Binary Tree Paths
  • 226. Invert Binary Tree
  • 111. Minimum Depth of Binary Tree
  • 110. Balanced Binary Tree
  • 108. Convert Sorted Array to Binary Search Tree
  • 104. Maximum Depth of Binary Tree
  • 101. Symmetric Tree
  • 100. Same Tree
  • 653 Two Sum IV - Input is a BST
  • 112 Path Sum
  • 167 Two Sum II - Input Array Is Sorted
  • 783. Minimum Distance Between BST Nodes
  • 872. Leaf-Similar Trees
  • 897. Increasing Order Search Tree
  • 938. Range Sum of BST
  • 965. Univalued Binary Tree
  • 993. Cousins in Binary Tree
  • 1022. Sum of Root To Leaf Binary Numbers
  • 703. Kth Largest Element in a Stream
  • 310. Minimum Height Trees
  • 96. Unique Binary Search Trees
  • 95. Unique Binary Search Trees II
  • 98. Validate Binary Search Tree
  • 99. Recover Binary Search Tree

winter break

• 909. Snakes and Ladders
• 198. House Robber
• 1094. Car Pooling
• 413. Arithmetic Slices
• 688. Knight Probability in Chessboard
• 5. Longest Palindromic Substring
• 1817. Finding the Users Active Minutes
• 328. Odd Even Linked List
• 2134. Minimum Swaps to Group All 1's Together II
• 1695. Maximum Erasure Value
• 1910. Remove All Occurrences of a Substring
• 1347. Minimum Number of Steps to Make Two Strings Anagram
• 306. Additive Number
• 1849. Splitting a String Into Descending Consecutive Values
• 525. Contiguous Array
• 209. Minimum Size Subarray Sum
• 1838. Frequency of the Most Frequent Element
• 374. Guess Number Higher or Lower
• 821. Shortest Distance to a Character
• 1624. Largest Substring Between Two Equal Characters
• 300. Longest Increasing Subsequence
• 1560. Most Visited Sector in a Circular Track
• 1221. Split a String in Balanced Strings
• 1502. Can Make Arithmetic Progression From Sequence
• 1071. Greatest Common Divisor of Strings
• 2114. Maximum Number of Words Found in Sentences
• 35. Search Insert Position
• 507. Perfect Number
• 1844. Replace All Digits with Characters
• 21. Merge Two Sorted Lists
• 561. Array Partition I
• 455. Assign Cookies
• 409. Longest Palindrome

💲 Stock

• Stock Problem
  • 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

2022.Jan.12

• 1 Two sums
• 2. Add Two Numbers
• 3. Longest Substring Without Repeating Characters
• 6. Zigzag Conversion
• 7. Reverse Integer
• 8. String to Integer (atoi)

2022.Jan.13

• 9. Palindrome Number
• 11. Container With Most Water
• 12. Integer to Roman
• 13. Roman to Integer
• 14. Longest Common Prefix
• 15. 3Sum
• 16. 3Sum Closest

2022.JAN.14

• 17. Letter Combinations of a Phone Number
• 18. 4Sum
• 19. Remove Nth Node From End of List
• 20. Valid Parentheses
• 22. Generate Parentheses
• 24. Swap Nodes in Pairs

2022.JAN.15

• UTEK Programming I
• UTEK Programming II

2022.JAN.16

• 26. Remove Duplicates from Sorted Array
• 27. Remove Element
• 28. Implement strStr()
• 29. Divide Two Integers
• 31. Next Permutation
• 36. Valid Sudoku
• 38. Count and Say

2022.JAN.17

• 33. Search in Rotated Sorted Array
• 39. Combination Sum
• 40. Combination Sum II
• 46. Permutations1
• 47. Permutations II

2022.JAN.18

• 34. Find First and Last Position of Element in Sorted Array
• 43. Multiply Strings
• 45. Jump Game II
• 48. Rotate Image
• 49. Group Anagrams

2022.JAN.19

• 50. Pow(x, n)
• 54. Spiral Matrix
• 55. Jump Game
• 56. Merge Intervals

2022.JAN.20

• 57. Insert Interval
• 59. Spiral Matrix II
• 61. Rotate List
• 62. Unique Paths
• 63. Unique Paths II

2022.JAN.21

• 64. Minimum Path Sum
• 71. Simplify Path
• 73. Set Matrix Zeroes
• 74. Search a 2D Matrix
• 75. Sort Colors

2022.JAN.22

• 77. Combinations
• 78. Subsets
• 79. Word Search
• 80. Remove Duplicates from Sorted Array II
• 81. Search in Rotated Sorted Array II

2022.JAN.23

• 82. Remove Duplicates from Sorted List II
• 83. Remove Duplicates from Sorted List
• 86. Partition List
• 89. Gray Code
• 90. Subsets II
• 91. Decode Ways

2022.JAN.24

• 92. Reverse Linked List II
• 93. Restore IP Addresses
• 97. Interleaving String
• 102. Binary Tree Level Order Traversal
• 103. Binary Tree Zigzag Level Order Traversal

2022.JAN.25

• 105. Construct Binary Tree from Preorder and Inorder Traversal
• 106. Construct Binary Tree from Inorder and Postorder Traversal
• 107. Binary Tree Level Order Traversal II
• 109. Convert Sorted List to Binary Search Tree
• 113. Path Sum II

2022.JAN.26

• 114. Flatten Binary Tree to Linked List
• 116. Populating Next Right Pointers in Each Node
• 117. Populating Next Right Pointers in Each Node II
• 120.Triangle
• 128. Longest Consecutive Sequence

2022.JAN.27

• 129. Sum Root to Leaf Numbers
• 130. Surrounded Regions
• 131. Palindrome Partitioning
• 134. Gas Station
• 137. Single Number II

2022.JAN.28

• 139. Word Break
• 142. Linked List Cycle II
• 143. Reorder List
• 150. Evaluate Reverse Polish Notation
• 151. Reverse Words in a String

2022.JAN.29

• 152. Maximum Product Subarray
• 153. Find Minimum in Rotated Sorted Array
• 162. Find Peak Element
• 165. Compare Version Numbers
• 172. Factorial Trailing Zeroes

2022.JAN.30

• 179. Largest Number
• 187. Repeated DNA Sequences
• 189. Rotate Array
• 199. Binary Tree Right Side View
• 200. Number of Islands

2022.JAN.31

• 204. Count Primes
• 207. Course Schedule
• 213. House Robber II
• 215. Kth Largest Element in an Array
• 216. Combination Sum III

2022.FEB.2

• 220. Contains Duplicate III
• 221. Maximal Square
• 222. Count Complete Tree Nodes
• 223. Rectangle Area
• 227. Basic Calculator II

2022.FEB.3

• 229. Majority Element II
• 230. Kth Smallest Element in a BST
• 236. Lowest Common Ancestor of a Binary Tree
• 238. Product of Array Except Self
• 240. Search a 2D Matrix II

2022.FEB.5

• 241. Different Ways to Add Parentheses
• 264. Ugly Number II

2022.FEB.19

• 274. H-Index
• 275. H-Index II
• 279. Perfect Squares
• 287. Find the Duplicate Number
• 289. Game of Life

2022.FEB.20

• 313. Super Ugly Number
• 316. Remove Duplicate Letters
• 319. Bulb Switcher
• 322. Coin Change
• 324. Wiggle Sort II

2022.FEB.21

• 331. Verify Preorder Serialization of a Binary Tree
• 334. Increasing Triplet Subsequence
• 337. House Robber III
• 343. Integer Break
• 347. Top K Frequent Elements

2022.FEB.22

• 357. Count Numbers with Unique Digits
• 368. Largest Divisible Subset
• 372. Super Pow
• 375. Guess Number Higher or Lower II
• 376. Wiggle Subsequence

2022.FEB.23

• 377. Combination Sum IV
• 378. Kth Smallest Element in a Sorted Matrix
• 386. Lexicographical Numbers
• 388. Longest Absolute File Path
• 390. Elimination Game

2022.FEB.24

• 393. UTF-8 Validation
• 394. Decode String
• 395. Longest Substring with At Least K Repeating Characters
• 396. Rotate Function
• 397. Integer Replacement

2022.FEB.25

• 400. Nth Digit
• 402. Remove K Digits
• 406. Queue Reconstruction by Height
• 416. Partition Equal Subset Sum
• 419. Battleships in a Board

Week 2022.FEB.28

• 423. Reconstruct Original Digits from English
• 424. Longest Repeating Character Replacement
• 433. Minimum Genetic Mutation
• 435. Non-overlapping Intervals
• 436. Find Right Interval
• 437. Path Sum III
• 438. Find All Anagrams in a String
• 442. Find All Duplicates in an Array
• 443. String Compression
• 445. Add Two Numbers II
• 447. Number of Boomerangs
• 450. Delete Node in a BST
• 451. Sort Characters By Frequency
• 452. Minimum Number of Arrows to Burst Balloons

Week March 7th

• 453. Minimum Moves to Equal Array Elements
• 454. 4Sum II
• 456. 132 Pattern
• 457. Circular Array Loop
• 462. Minimum Moves to Equal Array Elements II
• 464. Can I Win
• 467. Unique Substrings in Wraparound String
• 468. Validate IP Address
• 10. Regular Expression Matching

Week April 15th

• 470. Implement Rand10() Using Rand7()
• 473. Matchsticks to Square
• 474. Ones and Zeroes
• 475. Heaters