squxq / leetcode

LeetCode problems solutions. A journal of my problem-solving journey.

LeetCode Problem Solutions

Welcome to my LeetCode Problem Solutions repository! This is a record of my journey as I solve various LeetCode problems to improve my coding skills and deepen my understanding of algorithms and data structures. In this repository, you'll find solutions to a wide range of LeetCode problems, along with explanations and code implementations.

Table of Contents

• Introduction
• Repository Structure
• Problem Solving Approach
• List of Problems
• Contributing
• License

Introduction

LeetCode is a popular platform for practicing coding and algorithmic problem-solving. This repository serves as my personal collection of LeetCode problem solutions, which I use to track my progress, learn from my mistakes, and share my solutions with others who may find them helpful.

Repository Structure

This repository is organized as follows:

• problems: This directory contains subdirectories for each problem category. Within each category subdirectory, you will find individual problem solutions, each in its own directory.

  • Example: problems/array/merge-sorted-array contains solutions for the "Merge Sorted Array" problem.

• resources: This directory includes any relevant resources, notes, or templates that I use during problem-solving sessions.

• scripts: Some problems may require auxiliary scripts or utilities. You can find those in this directory.

Problem Solving Approach

My approach to solving LeetCode problems typically involves the following steps:

1. Understanding the Problem: I carefully read and understand the problem statement, making note of any special requirements, constraints, or edge cases.

2. Planning and Pseudocode: Before jumping into coding, I plan my approach, sketch out a pseudocode solution, and identify key data structures and algorithms to use.

3. Coding: I implement the solution in my preferred programming language, ensuring clean, well-documented code.

4. Testing: I thoroughly test my solution using sample test cases, edge cases, and custom test cases to verify its correctness.

5. Optimization: If necessary, I optimize my initial solution for better performance or memory usage. I also consider alternative approaches and compare their efficiency.

6. Explanation: I provide explanations of my solutions, including time and space complexity analysis, to help others understand the thought process behind the code.

7. Documentation: I update this README.md file with links to the solved problems and their corresponding explanations.

List of Problems

#	Title	Topic	Solution	Difficulty
88	Merge Sorted Array	Algorithms	TypeScript	Easy
27	Remove Element	Algorithms	TypeScript	Easy
26	Remove Duplicates from Sorted Array	Algorithms	TypeScript	Easy
80	Remove Duplicates from Sorted Array II	Algorithms	TypeScript	Medium
169	Majority Element	Algorithms	TypeScript	Easy
274	H-Index	Algorithms	TypeScript	Medium
13	Roman to Integer	Algorithms	TypeScript	Easy
58	Length of Last Word	Algorithms	TypeScript	Easy
189	Rotate Array	Algorithms	TypeScript	Medium
121	Best Time to Buy and Sell Stock	Algorithms	TypeScript	Easy
28	Find the Index of the First Occurrence in a String	Algorithms	TypeScript	Easy
14	Longest Common Prefix	Algorithms	TypeScript	Easy
55	Jump Game	Algorithms	TypeScript	Medium
1768	Merge Strings Alternately	Algorithms	TypeScript	Easy
1071	Greatest Common Divisor of Strings	Algorithms	TypeScript	Easy
1431	Kids With the Greatest Number of Candies	Algorithms	TypeScript	Easy
605	Can Place Flowers	Algorithms	TypeScript	Easy
345	Reverse Vowels of a String	Algorithms	TypeScript	Easy
2215	Find the Difference of Two Arrays	Algorithms	TypeScript	Easy
649	Dota2 Senate	Algorithms	TypeScript	Medium
1631	Path With Minimum Effort	Algorithms	TypeScript	Medium
319	Bulb Switcher	Algorithms	TypeScript	Medium
1584	Min Cost to Connect All Points	Algorithms	TypeScript	Medium
287	Find the Duplicate Number	Algorithms	TypeScript	Medium
1337	The K Weakest Rows in a Matrix	Algorithms	TypeScript	Easy
258	Add Digits	Algorithms	TypeScript	Easy
1491	Average Salary Excluding the Minimum and Maximum Salary	Algorithms	TypeScript	Easy
1822	Sign of the Product of an Array	Algorithms	TypeScript	Easy
1572	Matrix Diagonal Sum	Algorithms	TypeScript	Easy
703	Kth Largest Element in a Stream	Algorithms	TypeScript	Easy
1603	Design Parking System	Algorithms	TypeScript	Easy
1658	Minimum Operations to Reduce X to Zero	Algorithms	TypeScript	Medium
118	Pascal's Triangle	Algorithms	TypeScript	Easy
844	Backspace String Compare	Algorithms	TypeScript	Easy
119	Pascal's Triangle II	Algorithms	TypeScript	Easy
700	Search in a Binary Search Tree	Algorithms	TypeScript	Easy
108	Convert Sorted Array to Binary Search Tree	Algorithms	TypeScript	Easy
530	Minimum Absolute Difference in BST	Algorithms	TypeScript	Easy
501	Find Mode in Binary Search Tree	Algorithms	TypeScript	Easy
653	Two Sum IV - Input is a BST	Algorithms	TypeScript	Easy
783	Minimum Distance Between BST Nodes	Algorithms	TypeScript	Easy
897	Increasing Order Search Tree	Algorithms	TypeScript	Easy
938	Range Sum of BST	Algorithms	TypeScript	Easy
1382	Balance a Binary Search Tree	Algorithms	TypeScript	Medium
1305	All Elements in Two Binary Search Trees	Algorithms	TypeScript	Medium
230	Kth Smallest Element in a BST	Algorithms	TypeScript	Medium
96	Unique Binary Search Trees	Algorithms	TypeScript	Medium
701	Insert into a Binary Search Tree	Algorithms	TypeScript	Medium
94	Binary Tree Inorder Traversal	Algorithms	TypeScript	Easy
100	Same Tree	Algorithms	TypeScript	Easy
101	Symmetric Tree	Algorithms	TypeScript	Easy
104	Maximum Depth of Binary Tree	Algorithms	TypeScript	Easy
110	Balanced Binary Tree	Algorithms	TypeScript	Easy
111	Minimum Depth of Binary Tree	Algorithms	TypeScript	Easy
112	Path Sum	Algorithms	TypeScript	Easy
144	Binary Tree Preorder Traversal	Algorithms	TypeScript	Easy
145	Binary Tree Postorder Traversal	Algorithms	TypeScript	Easy
222	Count Complete Tree Nodes	Algorithms	TypeScript	Easy
226	Invert Binary Tree	Algorithms	TypeScript	Easy
257	Binary Tree Paths	Algorithms	TypeScript	Easy
404	Sum of Left Leaves	Algorithms	TypeScript	Easy
543	Diameter of Binary Tree	Algorithms	TypeScript	Easy
67	Add Binary	Algorithms	TypeScript	Easy
559	Maximum Depth of N-ary Tree	Algorithms	TypeScript	Easy
563	Binary Tree Tilt	Algorithms	TypeScript	Easy
572	Subtree of Another Tree	Algorithms	TypeScript	Easy
1662	Check If Two String Arrays are Equivalent	Algorithms	TypeScript	Easy
1160	Find Words That Can Be Formed by Characters	Algorithms	TypeScript	Easy
1266	Minimum Time Visiting All Points	Algorithms	TypeScript	Easy
2264	Largest 3-Same-Digit Number in String	Algorithms	TypeScript	Easy
1688	Count of Matches in Tournament	Algorithms	TypeScript	Easy
1716	Calculate Money in Leetcode Bank	Algorithms	TypeScript	Easy
1903	Largest Odd Number in String	Algorithms	TypeScript	Easy
606	Construct String from Binary Tree	Algorithms	TypeScript	Easy
867	Transpose Matrix	Algorithms	TypeScript	Easy
1287	Element Appearing More Than 25% In Sorted Array	Algorithms	TypeScript	Easy
1464	Maximum Product of Two Elements in an Array	Algorithms	TypeScript	Easy
1582	Special Positions in a Binary Matrix	Algorithms	TypeScript	Easy
151	Reverse Words in a String	Algorithms	TypeScript	Medium
443	String Compression	Algorithms	TypeScript	Medium
2482	Difference Between Ones and Zeros in Row and Column	Algorithms	TypeScript	Medium
1436	Destination City	Algorithms	TypeScript	Easy
242	Valid Anagram	Algorithms	TypeScript	Easy
2353	Design a Food Rating System	Algorithms	TypeScript	Medium
1913	Maximum Product Difference Between Two Pairs	Algorithms	TypeScript	Easy
661	Image Smoother	Algorithms	TypeScript	Easy
2706	Buy Two Chocolates	Algorithms	TypeScript	Easy
1637	Widest Vertical Area Between Two Points Containing No Points	Algorithms	TypeScript	Medium
1422	Maximum Score After Splitting a String	Algorithms	TypeScript	Easy
1496	Path Crossing	Algorithms	TypeScript	Easy
1758	Minimum Changes To Make Alternating Binary String	Algorithms	TypeScript	Easy
91	Decode Ways	Algorithms	TypeScript	Medium
1155	Number of Dice Rolls With Target Sum	Algorithms	TypeScript	Medium
1578	Minimum Time to Make Rope Colorful	Algorithms	TypeScript	Medium
1531	String Compression II	Algorithms	TypeScript	Hard
1335	Minimum Difficulty of a Job Schedule	Algorithms	TypeScript	Hard
1897	Redistribute Characters to Make All Strings Equal	Algorithms	TypeScript	Easy
1624	Largest Substring Between Two Equal Characters	Algorithms	TypeScript	Easy
455	Assign Cookies	Algorithms	TypeScript	Easy
2610	Convert an Array Into a 2D Array With Conditions	Algorithms	TypeScript	Medium
2125	Number of Laser Beams in a Bank	Algorithms	TypeScript	Medium
2870	Minimum Number of Operations to Make Array Empty	Algorithms	TypeScript	Medium
300	Longest Increasing Subsequence	Algorithms	TypeScript	Medium
1235	Maximum Profit in Job Scheduling	Algorithms	TypeScript	Hard
446	Arithmetic Slices II - Subsequence	Algorithms	TypeScript	Hard
238	Product of Array Except Self	Algorithms	TypeScript	Medium
872	Leaf-Similar Trees	Algorithms	TypeScript	Easy
2385	Amount of Time for Binary Tree to Be Infected	Algorithms	TypeScript	Medium
1026	Maximum Difference Between Node and Ancestor	Algorithms	TypeScript	Medium
1704	Determine if String Halves Are Alike	Algorithms	TypeScript	Easy
334	Increasing Triplet Subsequence	Algorithms	TypeScript	Medium
1347	Minimum Number of Steps to Make Two Strings Anagram	Algorithms	TypeScript	Medium
3005	Count Elements With Maximum Frequency	Algorithms	TypeScript	Easy
1657	Determine if Two Strings Are Close	Algorithms	TypeScript	Medium
2225	Find Players With Zero or One Losses	Algorithms	TypeScript	Medium
380	Insert Delete GetRandom O(1)	Algorithms	TypeScript	Medium
1207	Unique Number of Occurrences	Algorithms	TypeScript	Easy
70	Climbing Stairs	Algorithms	TypeScript	Easy
931	Minimum Falling Path Sum	Algorithms	TypeScript	Medium
907	Sum of Subarray Minimums	Algorithms	TypeScript	Medium
198	House Robber	Algorithms	TypeScript	Medium
645	Set Mismatch	Algorithms	TypeScript	Easy
1239	Maximum Length of a Concatenated String with Unique Characters	Algorithms	TypeScript	Medium
1457	Pseudo-Palindromic Paths in a Binary Tree	Algorithms	TypeScript	Medium
1143	Longest Common Subsequence	Algorithms	TypeScript	Medium
576	Out of Boundary Paths	Algorithms	TypeScript	Medium
...	...	...	...	...

In this table:

• # represents the problem number.
• Title contains a link to the problem's directory.
• Topic categorizes the problems into the domain they represent (e.g. Algorithms, Database, Shell).
• Solution indicates the programming language used for the solution.
• Difficulty denotes the difficulty level of the problem (e.g., Easy, Medium, Hard).

You can add more rows to the table as you solve additional problems and provide links to the corresponding problem directories.

Contributing

While this repository primarily serves as a record of my LeetCode problem-solving journey, contributions, feedback, and discussions are welcome! If you have suggestions for improving my solutions or spot any errors, please feel free to open an issue or submit a pull request.

License

This repository is licensed under the MIT License. You are welcome to use, modify, and distribute the code in this repository, but please provide attribution by linking back to this repository.