LeetCode

This repository is used for recording my LeetCode challenges.

Already done

Accepted	Title	Difficulty	Date	Category	Language
✅	1. Two Sum	Easy	2020.07.31/2022.09.02/2025.03.30/2025.04.05/2025.07.28		Python
🆙	2. Add Two Numbers	Medium	2022.08.07		Python
✅⛔	3. Longest Substring Without Repeating Characters	Medium	2020.08.02/2025.04.07/2025.04.08		Python
✅	4. Median of Two Sorted Arrays	Hard	2020.08.01		Python
	5. Longest Palindromic Substring	Medium
✅	7. Reverse Integer	Medium	2025.06.19		Python
✅	8. String to Integer (atoi)	Medium	2025.06.20		Python
✅	9. Palindrome Number	Easy	2022.05.16/2025.05.16/2025.06.26		Go/Python
⛔✅	11. Container With Most Water	Easy	2022.10.02/2023.08.25/2025.05.17		Python
⛔✅	12. Integer to Roman	Medium	2025.06.25	Array / String	Python
✅	13. Roman to Integer	Easy	2022.05.17/2025.05.18		Go/Python
✅	14. Longest Common Prefix	Easy	2022.05.18/2025.05.19		Python / Go
	15. 3Sum	Medium
⛔✅	17. Letter Combinations of a Phone Number	Medium	2025.07.02-03,05	Backtracking	Python
✅	20. Valid Parentheses	Easy	2025.04.05		Python
✅⛔	21. Merge Two Sorted Lists	Easy	2022.11.09/2025.05.04-07/2025.07.01/2025.07.31	Linked List	Python
✅	26. Remove Duplicates from Sorted Array	Easy	2025.04.05		Python
✅	27. Remove Element	Easy	2023.09.21		Python
✅	28. Find the Index of the First Occurrence in a String	Easy	2025.04.14/2025.05.21		Python
✅⛔	34. Find First and Last Position of Element in Sorted Array	Medium	2025/05/22		Python
✅	35. Search Insert Position	Easy	2025.04.11/2025.04.14/2025.05.01/2025.05.24/2025.06.05		Python
⛔	36. Valid Sudoku	Medium	2025.04.16/2025.04.16	Matrix	Python
✅⛔	45. Jump Game II	Medium	2025.05.14	Array / String	Python
✅	49. Group Anagrams	Medium	2025.04.05		Python
⛔✅	50. Pow(x, n)	Medium	2025.04.18/2025.04.19/2025.06.13	Math	Python
✅	53. Maximum Subarray	Medium	2022.10.03/2025.06.07	Kadane's Algorithm	Python
⛔	54. Spiral Matrix	Medium	2025.06.24	Matrix	Python
✅	55. Jump Game	Medium	2025.05.13	Array / String	Python
✅	56. Merge Intervals	Medium	2021.12.25		Python
✅	57. Insert Interval	Medium	2025.04.26	Intervals	Python
✅	58. Length of Last Word	Easy	2025.03.31		Python
✅	66. Plus One	Easy	2025.04.20	Math	Python
✅	67. Add Binary	Easy	2025.04.12/2025.04.13/2025.04.14		Python
✅	69. Sqrt(x)	Easy	2025.04.17/2025.06.15	Math	Python
✅	70. Climbing Stairs	Easy	2023.03.27/2025.06.04/2025.06.16/2025.06.30/2025.07.29	DP	Python
✅	71. Simplify Path	Medium	2025.04.05/2025.04.06		Python
⛔✅	74. Search a 2D Matrix	Medium	2025.06.06	Binary Search	Python
⛔✅	83. Remove Duplicates from Sorted List	Easy	2025.07.30		Python
✅	88. Merge Sorted Array	Easy	2025.03.26		Python
✅	94. Binary Tree Inorder Traversal	Easy	2025.06.22		Python
✅	100. Same Tree	Easy	2022.10.19		Python
⛔	101. Symmetric Tree	Easy	2025.04.25	Binary Tree General	Python
⛔✅	102. Binary Tree Level Order Traversal	Medium	2025.05.26-28/06.01	Binary Tree BFS	Python
⛔✅	104. Maximum Depth of Binary Tree	Easy	2022.10.12/2023.08.28/2025.08.28	Binary Tree - DFS	Python
❌	108. Convert Sorted Array to Binary Search Tree	Easy	2025.03.31/2025.04.15/2025.07.05		Python
⛔	112. Path Sum	Easy	2025.05.08	Binary Tree General	Python
✅	118. Pascal's Triangle	Easy	2025.08.01		Python
⛔	120. Triangle	Medium	2025.07.06
✅	121. Best Time to Buy and Sell Stock	Easy	2022.09.30		Python
✅	122. Best Time to Buy and Sell Stock II	Medium	2025.05.12	Array / String	Python
✅	128. Longest Consecutive Sequence	Medium	2025.05.09	Hashmap	Python
⛔	134. Gas Station	Medium	2025.04.21	Array / String	Python
✅	136. Single Number	Easy	2023.08.30		Python
✅	141. Linked List Cycle	Easy	2022.11.04		Python
⛔	148. Sort List	Medium	2025.05.25	Divide & Conquer	Python
✅	150. Evaluate Reverse Polish Notation	Medium	2025.04.24	Stack	Python
✅	151. Reverse Words in a String	Medium	2023.08.17		Python
✅	155. Min Stack	Medium	2025.04.23	Stack	Python
⛔	162. Find Peak Element	Medium	2023.09.11		Python
✅	167. Two Sum II - Input Array Is Sorted	Medium	2025.03.29		Python
✅	169. Majority Element	Easy	2025.04.20	Array / String	Python
✅	171. Excel Sheet Column Number	Easy	2025.04.30	Math / String	Python
⛔	175. Combine Two Tables	Easy	2025.07.07	Database	SQL
⛔✅	176. Second Highest Salary	Easy	2025.07.22	Database	SQL
⛔✅	178. Rank Scores	Medium	2025.07.23	Database	SQL
⛔✅	180. Consecutive Numbers	Medium	2025.07.24	Database	SQL
⛔	181. Employees Earning More Than Their Managers	Easy	2025.07.08	Database	SQL
✅	182. Duplicate Emails	Easy	2025.07.09	Database	SQL
⛔	183. Customers Who Never Order	Easy	2025.07.10	Database	SQL
⛔✅	189. Rotate Array	Medium	2025.05.11	Array / String	Python
✅	191. Number of 1 Bits	Easy	2025.04.28	Bit Manipulation	Python
⛔	196. Delete Duplicate Emails	Easy	2025.07.12	Database	SQL
⛔✅	197. Rising Temperature	Easy	2025.07.13	Database	SQL
⛔	198. House Robber	Medium	2023.09.16		Python
⛔✅	199. Binary Tree Right Side View	Medium	2025.08.04	Binary Tree - BFS	Python
⛔✅	200. Number of Islands	Medium	2025.05.15	Graph General	Python
⛔✅	201. Bitwise AND of Numbers Range	Medium	2025.06.28	Bit Manipulation	Python
✅	202. Happy Number	Easy	2025.04.05		Python
✅	205. Isomorphic Strings	Easy	2025.04.04		Python
✅	206. Reverse Linked List	Easy	2022.10.19/2023.08.24/2025.05.30-06.01/2025.08.12		Python
✅	208. Implement Trie (Prefix Tree)	Medium	2025.08.22	Trie	Python
⛔	209. Minimum Size Subarray Sum	Medium	2025.04.06/2025.04.07/2025.06.02-03		Python
✅	215. Kth Largest Element in an Array	Medium	2023.08.31		Python
✅	217. Contains Duplicate	Easy	2022.09.30/2023.08.24		Python
⛔	219. Contains Duplicate II	Easy	2025.04.13		Python
❌	222. Count Complete Tree Nodes	Easy	2025.04.22	Binary Tree General	Python
✅	226. Invert Binary Tree	Easy	2022.10.20		Python
✅	227. Basic Calculator II	Medium	2021.12.25		Python
✅	228. Summary Ranges	Easy	2025.04.02		Python
✅	238. Product of Array Except Self	Medium	2022.10.10/2023.09.08		Python
✅	242. Valid Anagram	Easy	2022.11.02		Python
✅	268. Missing Number	Easy	2025.08.06		Python
🟰	274. H-Index	Medium	2025.04.29	Array / String	Python
✅	278. First Bad Version	Medium	2021.12.26		Python
⛔✅	283. Move Zeroes	Easy	2023.07.01/2025.09.02	Two Pointers	Python
✅	290. Word Pattern	Easy	2025.04.04		Python
⛔✅	328. Odd Even Linked List	Medium	2025.08.11	Linked List	Python
⛔	334. Increasing Triplet Subsequence	Medium	2023.09.07		Python
⛔	338. Counting Bits	Easy	2023.09.09		Python
✅	347. Top K Frequent Elements	Medium	2022.11.10		Python
✅	345. Reverse Vowels of a String	Easy	2023.08.16		Python
✅	374. Guess Number Higher or Lower	Easy	2023.08.29/2025.08.25	Binary Search	Python
✅	380. Insert Delete GetRandom O(1)	Medium	2025.06.17/2025.06.18	Array / String	Python
✅	383. Ransom Note	Easy	2025.04.03		Python
✅	392. Is Subsequence	Easy	2023.08.17/2025.09.02	Two Pointers	Python
⛔	394. Decode String	Medium	2025.05.01
✅⛔	435. Non-overlapping Intervals	Medium	2025.08.21	Intervals	Python
⛔	443. String Compression	Medium	2023.08.20		Python
✅	452. Minimum Number of Arrows to Burst Balloons	Medium	2025.04.27	Intervals	Python
✅⛔	455. Assign Cookies	Easy	2025.07.27	Greedy	Python
✅	476._Number Complement	Easy	2021.12.27		Python
✅⛔	511. Game Play Analysis I	Easy	2025.07.14	Database	SQL
⛔	530. Minimum Absolute Difference in BST	Easy	2025.04.09/2025.04.10/2025.06.10		Python
✅	577. Employee Bonus	Easy	2025.07.15	Database	SQL
✅	584. Find Customer Referee	Easy	2025.07.16	Database	SQL
✅⛔	586. Customer Placing the Largest Number of Orders	Easy	2025.07.17	Database	SQL
✅	595. Big Countries	Easy	2025.07.18	Database	SQL
✅	596. Classes With at Least 5 Students	Easy	2025.07.19	Database	SQL
✅	605. Can Place Flowers	Easy	2023.08.15		Python
✅⛔	607. Sales Person	Easy	2025.07.20	Database	SQL
✅⛔	610. Triangle Judgement	Easy	2025.07.21/07.22	Database	SQL
✅	637. Average of Levels in Binary Tree	Easy	2025.04.08/2025.04.09/2025.06.11		Python
✅⛔	643. Maximum Average Subarray I	Easy	2023.08.19/2025.09.03	Sliding Window	Python
✅⛔	649. Dota2 Senate	Medium	2025.08.09	Queue	Python
⛔	700. Search in a Binary Search Tree	Easy	2023.09.05		Python
✅	704. Binary Search	Medium	2021.12.26		Python
✅	724. Find Pivot Index	Easy	2023.08.22/2025.08.14	Prefix Sum	Python
✅	735. Asteroid Collision	Medium	2023.08.27		Python
✅⛔	739. Daily Temperatures	Medium	2025.08.22	Monotonic Stack	Python
⛔	746. Min Cost Climbing Stairs	Easy	2023.09.04		Python
✅⛔	872. Leaf-Similar Trees	Easy	2025.05.02/2025.08.05/2025.08.30	Binary Tree - DFS	Python
⛔	875. Koko Eating Bananas	Medium	2025.08.26	Binary Search	Python
✅⛔	901. Online Stock Span	Medium	2025.08.24	Monotonic Stack	Python
✅⛔	918. Maximum Sum Circular Subarray	Medium	2025.06.08-09	Kadane's Algorithm	Python
✅	933. Number of Recent Calls	Easy	2023.08.23/2025.08.10/2025.08.27	Queue	Python
✅	973. K Closest Points to Origin	Medium	2021.12.26		Python
✅	977. Squares of a Sorted Array	Easy	2021.12.27		Python
⛔✅	1004. Max Consecutive Ones III	Medium	2023.09.13/2025.08.09		Python
✅	1071. Greatest Common Divisor of Strings	Easy	2023.08.14		Python
✅	1114. Print in Order	Easy	2025.07.26		Python
⛔	1137. N-th Tribonacci Number	Easy	2023.09.03		Python
⛔✅	1161. Maximum Level Sum of a Binary Tree	Medium	2025.08.31	Binary Tree - BFS	Python
✅	1207. Unique Number of Occurrences	Easy	2023.08.22/2025.08.18	Hash Map / Set	Python
✅⛔	1268. Search Suggestions System	Medium	2025.08.23	Trie	Python
✅	1431. Kids With the Greatest Number of Candies	Easy	2023.08.15		Python
⛔	1448. Count Good Nodes in Binary Tree	Medium	2025.08.16	Binary Tree - DFS	Python
❌	1456. Maximum Number of Vowels in a Substring of Given Length	Medium	2023.09.02		Python
❌	1493. Longest Subarray of 1's After Deleting One Element	Medium	2023.09.19		Python
✅	1657. Determine if Two Strings Are Close	Medium	2023.09.01		Python
✅	1679. Max Number of K-Sum Pairs	Medium	2023.09.07		Python
✅	1732. Find the Highest Altitude	Easy	2023.08.20/2025.08.13		Python
✅	1768. Merge Strings Alternately	Easy	2023.06.12		Python
✅	1957. Delete Characters to Make Fancy String	Easy	2025.08.03		Python
⛔✅	2095. Delete the Middle Node of a Linked List	Medium	2025.06.01	Linked List	Python
✅	2215. Find the Difference of Two Arrays	Easy	2023.08.22/2025.08.17	Hash Map / Set	Python
⛔	2300. Successful Pairs of Spells and Potions	Medium	2025.05.03
✅	2352. Equal Row and Column Pairs	Medium	2023.09.10/2025.08.19		Python
✅	2390. Removing Stars From a String	Medium	2023.08.26/2025.08.17	Stack	Python
❌	2561. Rearranging Fruits	Hard	2025.08.02		Python

August Daily Challenges

Days	Title	Accepted	Date
Day1	Detect Capital	✅	2020.08.01
Day2	Design HashSet	✅	2020.08.02
Day3	Valid Palindrome	✅	2020.08.03
Day4	Power of Four	✅	2020.08.04
Day5	Add and Search Word - Data structure design	Fail	2020.08.05
Day6	Find All Duplicates in an Array	✅	2020.08.06
Day7	Vertical Order Traversal of a Binary Tree	Fail	2020.08.07