LeetCode Solutions

Welcome to a robust and versatile repository of LeetCode solutions! This repository is a treasure trove for coding enthusiasts, educators, students, and professionals who are preparing for technical interviews or enhancing their coding skills.

What You'll Find Here

Wide Range of Problems: Our collection includes an extensive range of LeetCode problems, covering various topics and difficulty levels – from Easy to Hard.
Multi-Language Support: We offer solutions in several programming languages, including Python, C++, JavaScript, SQL, and TypeScript, catering to a diverse coding community.
Organized and Accessible: Each solution is meticulously organized by difficulty and language, making it easy to navigate and find what you need.
In-Depth Explanations: You'll find README files in each problem folder with detailed explanations of the problem, the approach taken, and a thorough walkthrough of the solution.

Statistics

Folder Structure

The solutions are organized as follows:

Difficulty: Problems are categorized into Easy, Medium, and Hard.
Languages: Solutions are available in multiple programming languages, including Python, C++, JavaScript, SQL, and TypeScript.
Problem Titles: Each problem is named after its LeetCode title.

Question List

#	Title	Solution	Difficulty & ReadMe
0001	Two Sum	Python, C++	Easy
0002	Add Two Numbers	C++	Medium
0003	Longest Substring Without Repeating Characters	Python, C++	Medium
0004	Median of Two Sorted Arrays	Python	Hard
0005	Longest Palindromic Substring	Python	Medium
0008	ZigZag Conversion	Python	Medium
0009	Palindrome Number	C++	Easy
0011	Container With Most Water	Python	Medium
0013	Roman to Integer	C++	Easy
0014	Longest Common Prefix	C++	Easy
0015	3Sum	Python, C++	Medium
0017	Letter Combinations of a Phone Number	Python	Medium
0018	4Sum	Python	Medium
0019	Remove Nth Node From End of List	C++	Medium
0020	Valid Parentheses	Python,C++	Easy
0021	Merge Two Sorted Lists	Python, C++	Easy
0022	Generate Parentheses	Python	Medium
0023	Merge k Sorted Lists	Python	Hard
0026	Remove Duplicates from Sorted Array	Python	Easy
0027	Remove Element	Python	Easy
0031	Next Permutation	Python	Medium
0033	Search in Rotated Sorted Array	Python	Medium
0034	Find First and Last Position of Element in Sorted Array	Python	Medium
0035	Search Insert Position	C++	Easy
0036	Valid Sudoku	Python, C++	Medium
0039	Combination Sum	Python	Medium
0042	Trapping Rain Water	Python	Hard
0045	Jump Game II	C++	Hard
0046	Permutations	C++	Medium
0048	Rotate Image	C++	Medium
0049	Group Anagrams	Python, JavaScript	Medium
0050	Pow(x, n)	Python	Medium
0053	Maximum Subarray	Python, C++	Easy
0054	Spiral Matrix	Python, C++	Medium
0055	Jump Game	C++	Medium
0056	Merge Intervals	Python, C++	Medium
0057	Insert Interval	Python	Hard
0058	Length of Last Word	Python	Easy
0059	Spiral Matrix II	C++	Medium
0062	Unique Paths	Python	Medium
0063	Unique Paths II	Python	Medium
0066	Plus One	Python	Easy
0067	Add Binary	Python	Easy
0068	Text Justification	Python	Hard
0070	Climbing Stairs	Python, C++	Easy
0074	Search a 2D Matrix	Python, C++	Medium
0075	Sort Colors	Python, C++	Medium
0076	Minimum Window Substring	Python	Hard
0077	Combinations	Python, C++	Medium
0078	Subsets	Python	Medium
0079	Word Search	Python	Medium
0081	Search in Rotated Sorted Array II	Python	Medium
0083	Remove Duplicates from Sorted List	C++	Easy
0084	Largest Rectangle in Histogram	Python	Hard
0086	Partition List	Python	Medium
0088	Merge Sorted Array	C++	Easy
0090	Subsets II	Python	Medium
0091	Decode Ways	Python	Medium
0092	Reverse Linked List II	Python	Medium
0094	Binary Tree Inorder Traversal	C++	Medium
0095	Unique Binary Search Trees II	Python	Medium
0097	Interleaving String	Python	Medium
0098	Validate Binary Search Tree	Python, C++	Medium
0101	Symmetric Tree	C++	Easy
0102	Binary Tree Level Order Traversal	Python, C++	Medium
0104	Maximum Depth of Binary Tree	Python, C++	Easy
0105	Construct Binary Tree from Preorder and Inorder Traversal	Python	Medium
0110	Balanced Binary Tree	Python	Easy
0112	Path Sum	C++	Easy
0116	Populating Next Right Pointers in Each Node	C++	Medium
0118	Pascal's Triangle	Python, C++	Easy
0119	Pascal's Triangle II	Python, C++	Easy
0120	Triangle	Python	Medium
0121	Best Time to Buy and Sell Stock	Python, C++	Easy
0125	Valid Palindrome	Python	Easy
0127	Word Ladder	Python	Medium
0128	Longest Consecutive Sequence	Python	Hard
0133	Clone Graph	Python	Medium
0135	Candy	Python	Hard
0136	Single Number	Python, C++	Easy
0137	Single Number II	Python	Medium
0138	Copy List with Random Pointer	Python	Medium
0139	Word Break	Python	Medium
0141	Linked List Cycle	Python, C++	Easy
0144	Binary Tree Preorder Traversal	C++	Medium
0145	Binary Tree Postorder Traversal	C++	Hard
0148	Sort List	Python	Medium
0150	Evaluate Reverse Polish Notation	Python	Medium
0153	Find Minimum in Rotated Sorted Array	Python	Medium
0155	Min Stack	Python	Easy
0159	Longest Substring with At Most Two Distinct Characters	Python	Medium
0167	Two Sum II - Input array is sorted	Python, C++	Easy
0168	Excel Sheet Column Title	Python	Easy
0169	Majority Element	Python, C++	Easy
0189	Rotate Array	C++	Medium
0190	Reverse Bits	Python	Easy
0191	Number of 1 Bits	Python	Easy
0198	House Robber	Python, C++	Easy
0199	Binary Tree Right Side View	Python	Medium
0200	Number of Islands	Python	Medium
0202	Happy Number	Python	Easy
0203	Remove Linked List Elements	C++	Easy
0205	Isomorphic Strings	Python	Easy
0206	Reverse Linked List	Python, C++, JavaScript	Easy
0207	Course Schedule	Python	Medium
0208	Implement Trie (Prefix Tree)	Python	Medium
0213	House Robber II	C++	Medium
0215	Kth Largest Element in an Array	Python	Medium
0217	Contains Duplicate	Python, C++, JavaScript	Easy
0224	Basic Calculator	Python	Hard
0225	Implement Stack using Queues	Python	Easy
0226	Invert Binary Tree	Python	Easy
0229	Majority Element II	Python	Medium
0230	Kth Smallest Element in a BST	Python	Medium
0231	Power of Two	C++	Easy
0232	Implement Queue using Stacks	Python, C++	Easy
0235	Lowest Common Ancestor of a Binary Search Tree	Python, C++	Easy
0236	Lowest Common Ancestor of a Binary Tree	Python	Medium
0238	Product of Array Except Self	Python	Medium
0239	Sliding Window Maximum	Python	Hard
0242	Valid Anagram	Python, C++, JavaScript	Easy
0271	Encode and Decode Strings	Python	Medium
0278	First Bad Version	Python, C++	Easy
0283	Move Zeroes	C++	Easy
0287	Find the Duplicate Number	Python	Medium
0295	Find Median from Data Stream	Python	Hard
0296	Best Meeting Point	Python	Hard
0297	Serialize and Deserialize Binary Tree	Python	Hard
0300	Longest Increasing Subsequence	Python	Medium
0310	Minimum Height Trees	Python	Medium
0316	Remove Duplicate Letters	Python	Hard
0322	Coin Change	Python	Medium
0332	Reconstruct Itinerary	Python	Medium
0338	Counting Bits	Python	Medium
0341	Flatten Nested List Iterator	Python	Medium
0342	Power of Four	Python	Easy
0343	Integer Break	Python	Medium
0344	Reverse String	C++	Easy
0346	Moving Average from Data Stream	Python	Easy
0347	Top K Frequent Elements	Python	Medium
0350	Intersection of Two Arrays II	C++	Easy
0358	Rearrange String k Distance Apart	Python	Hard
0377	Combination Sum IV	Python	Medium
0380	Insert Delete GetRandom O(1)	Python	Medium
0383	Ransom Note	Python, C++	Easy
0389	Find the Difference	Python	Easy
0392	Is Subsequence	Python	Easy
0403	Frog Jump	Python	Hard
0409	Longest Palindrome	Python	Easy
0416	Partition Equal Subset Sum	Python	Medium
0438	Find All Anagrams in a String	Python	Medium
0439	Ternary Expression Parser	Python	Medium
0446	Arithmetic Slices II - Subsequence	Python	Hard
0455	Assign Cookies	Python	Easy
0456	132 Pattern	Python	Medium
0458	Poor Pigs	Python	Hard
0459	Repeated Substring Pattern	Python	Easy
0486	Predict the Winner	Python	Medium
0487	Max Consecutive Ones II	Python	Medium
0490	The Maze	Python	Medium
0501	Find Mode in Binary Search Tree	Python	Easy
0505	The Maze II	Python	Medium
0509	Fibonacci Number	C++	Easy
0515	Find Largest Value in Each Tree Row	Python	Medium
0518	Coin Change 2	Python	Medium
0532	K-diff Pairs in an Array	Python	Easy
0540	Single Element in a Sorted Array	Python	Medium
0542	01 Matrix	Python, C++	Medium
0543	Diameter of Binary Tree	Python	Easy
0557	Reverse Words in a String III	C++	Easy
0561	Array Partition I	Python	Easy
0566	Reshape the Matrix	C++	Easy
0567	Permutation in String	C++	Medium
0573	Squirrel Simulation	Python	Medium
0584	Find Customer Referee	SQL	Easy
0595	Big Countries	SQL	Easy
0606	Construct String from Binary Tree	Python	Easy
0617	Merge Two Binary Trees	C++	Easy
0621	Task Scheduler	Python	Medium
0624	Maximum Distance in Arrays	Python	Easy
0646	Maximum Length of Pair Chain	Python	Medium
0653	Two Sum IV - Input is a BST	C++	Easy
0658	Find K Closest Elements	Python	Medium
0661	Image Smoother	Python	Easy
0664	Strange Printer	Python	Hard
0695	Max Area of Island	C++	Medium
0700	Search in a Binary Search Tree	C++	Easy
0701	Insert into a Binary Search Tree	C++	Medium
0704	Binary Search	Pythoon, C++	Easy
0706	Design HashMap	Python, C++	Easy
0712	Minimum ASCII Delete Sum for Two Strings	Python	Medium
0721	Accounts Merge	Python	Medium
0723	Candy Crush	Python	Medium
0725	Split Linked List in Parts	Python	Medium
0733	Flood Fill	Python, C++	Easy
0739	Daily Temperatures	Python	Medium
0746	Min Cost Climbing Stairs	Python, C++	Easy
0767	Reorganize String	Python	Medium
0779	K-th Symbol in Grammar	Python	Medium
0784	Letter Case Permutation	C++	Medium
0799	Champagne Tower	Python	Medium
0808	Soup Servings	Python	Medium
0815	Bus Routes	Python	Hard
0823	Binary Trees With Factors	Python	Medium
0844	Backspace String Compare	Python	Easy
0847	Shortest Path Visiting All Nodes	Python	Hard
0852	Peak Index in a Mountain Array	Python	Easy
0867	Transpose Matrix	Python	Easy
0872	Leaf-Similar Trees	Python	Easy
0875	Koko Eating Bananas	Python	Medium
0876	Middle of the Linked List	Python, C++	Easy
0880	Decoded String at Index	Python	Medium
0888	Fair Candy Swap	Python	Easy
0894	All Possible Full Binary Trees	Python	Medium
0896	Monotonic Array	Python	Easy
0905	Sort Array By Parity	Python	Easy
0907	Sum of Subarray Minimums	Python	Medium
0920	Number of Music Playlists	Python	Hard
0931	Minimum Falling Path Sum	Python	Medium
0935	Knight Dialer	Python	Medium
0938	Range Sum of BST	Python	Easy
0973	K Closest Points to Origin	Python	Medium
0977	Squares of a Sorted Array	C++	Easy
0981	Time Based Key-Value Store	Python	Medium
0994	Rotting Oranges	Python, C++	Medium
1026	Maximum Difference Between Node and Ancestor	Python	Medium
1048	Longest String Chain	Python	Medium
1057	Campus Bikes	Python	Medium
1060	Missing Element in Sorted Array	Python	Medium
1063	Number of Valid Subarrays	Python	Hard
1066	Campus Bikes II	Python	Medium
1071	Greatest Common Divisor of Strings	Python	Easy
1095	Find in Mountain Array	Python	Hard
1099	Two Sum Less Than K	Python	Easy
1120	Maximum Average Subtree	Python	Medium
1136	Parallel Courses	Python	Hard
1137	N-th Tribonacci Number	C++	Easy
1148	Article Views I	SQL	Easy
1155	Number of Dice Rolls With Target Sum	Python	Medium
1160	Find Words That Can Be Formed by Characters	Python	Easy
1165	Single Row Keyboard	Python	Easy
1183	Maximum Number of Ones	Python	Hard
1197	Minimum Knight Moves	Python	Medium
1199	Minimum Time to Build Blocks	Python	Hard
1203	Sort Items by Groups Respecting Dependencies	Python	Hard
1207	Unique Number of Occurrences	Python	Easy
1216	Valid Palindrome III	Python	Hard
1220	Count Vowels Permutation	Python	Hard
1235	Maximum Profit in Job Scheduling	Python	Hard
1265	Print Immutable Linked List in Reverse	C++	Medium
1266	Minimum Time Visiting All Points	Python	Easy
1269	Number of Ways to Stay in the Same Place After Some Steps	Python	Hard
1282	Group the People Given the Group Size They Belong To	Python	Medium
1287	Element Appearing More Than 25% In Sorted Array	Python	Easy
1326	Minimum Number of Taps to Open to Water a Garden	Python	Hard
1335	Minimum Difficulty of a Job Schedule	Python	Hard
1337	The K Weakest Rows in a Matrix	Python	Easy
1347	Minimum Number of Steps to Make Two Strings Anagram	Python	Medium
1356	Sort Integers by The Number of 1 Bits	Python	Easy
1359	Count All Valid Pickup and Delivery Options	Python	Hard
1361	Validate Binary Tree Nodes	Python	Medium
1420	Build Array Where You Can Find The Maximum Exactly K Comparisons	Python	Hard
1422	Maximum Score After Splitting a String	Python	Easy
1424	Diagonal Traverse II	Python	Medium
1425	Constrained Subsequence Sum	Python	Hard
1428	Leftmost Column with at Least a One	Python	Medium
1436	Destination City	Python	Easy
1441	Build an Array With Stack Operations	Python	Easy
1458	Max Dot Product of Two Subsequences	Python	Hard
1464	Maximum Product of Two Elements in an Array	Python	Easy
1470	Shuffle the Array	Python	Easy
1489	Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree	Python	Hard
1496	Path Crossing	Python	Easy
1512	Number of Good Pairs	Python	Easy
1531	String Compression II	Python	Hard
1535	Find the Winner of an Array Game	Python	Medium
1561	Maximum Number of Coins You Can Get	Python	Medium
1578	Minimum Deletion Cost to Avoid Repeating Letters	Python	Medium
1582	Special Positions in a Binary Matrix	Python	Easy
1584	Min Cost to Connect All Points	Python	Medium
1611	Minimum One Bit Operations to Make Integers Zero	Python	Hard
1615	Maximal Network Rank	Python	Medium
1630	Arithmetic Subarrays	Python	Medium
1631	Path With Minimum Effort	Python	Medium
1637	Widest Vertical Area Between Two Points Containing No Points	Python	Medium
1647	Minimum Deletions to Make Character Frequencies Unique	Python	Medium
1657	Determine if Two Strings Are Close	Python	Medium
1658	Minimum Operations to Reduce X to Zero	Python	Medium
1660	Correct a Binary Tree	Python	Medium
1662	Check If Two String Arrays are Equivalent	Python	Easy
1683	Invalid Tweets	SQL	Easy
1685	Sum of Absolute Differences in a Sorted Array	Python	Medium
1688	Count of Matches in Tournament	Python	Easy
1704	Determine if String Halves Are Alike	Python	Easy
1716	Calculate Money in Leetcode Bank	Python	Easy
1727	Largest Submatrix With Rearrangements	Python	Medium
1743	Restore the Array From Adjacent Pairs	Python	Medium
1757	Recyclable and Low Fat Products	SQL	Medium
1758	Minimum Changes To Make Alternating Binary String	Python	Easy
1759	Count Number of Homogenous Substrings	Python	Medium
1793	Maximum Score of a Good Subarray	Python	Hard
1802	Maximum Value at a Given Index in a Bounded Array	Python	Medium
1804	Implement Trie II (Prefix Tree)	Python	Medium
1814	Count Nice Pairs in an Array	Python	Medium
1838	Frequency of the Most Frequent Element	Python	Medium
1845	Seat Reservation Manager	Python	Medium
1846	Maximum Element After Decreasing and Rearranging	Python	Medium
1870	Minimum Speed to Arrive on Time	Python	Medium
1877	Minimize Maximum Pair Sum in Array	Python	Medium
1887	Reduction Operations to Make the Array Elements Equal	Python	Medium
1897	Redistribute Characters to Make All Strings Equal	Python	Easy
1903	Largest Odd Number in String	Python	Easy
1913	Maximum Product Difference Between Two Pairs	Python	Easy
1920	Build Array from Permutation	C++	Easy
1921	Eliminate Maximum Number of Monsters	Python	Medium
1930	Unique Length-3 Palindromic Subsequences	Python	Medium
1980	Find Unique Binary String	Python	Medium
2009	Minimum Number of Operations to Make Array Continuous	Python	Hard
2038	Remove Colored Pieces if Both Neighbors are the Same Color	Python	Medium
2050	Number of Different Integers in a String	Python	Easy
2125	Number of Laser Beams in a Bank	Python	Medium
2141	Maximum Running Time of N Computers	Python	Hard
2147	Number of Ways to Divide a Long Corridor	Python	Hard
2225	Find Players With Zero or One Losses	Python	Medium
2251	Number of Flowers in Full Bloom	Python	Hard
2264	Largest 3-Same-Digit Number in String	Python	Easy
2265	Count Nodes Equal to Average of Subtree	Python	Medium
2353	Design a Food Rating System	Python	Medium
2355	Maximum Number of Books You Can Take	Python	Hard
2361	Minimum Costs Using the Train Line	Python	Hard
2366	Minimum Replacements to Sort the Array	Python	Hard
2369	Check If There Is a Valid Partition for the Array	Python	Medium
2385	Amount of Time for Binary Tree to be Infected	Python	Medium
2391	Minimum Amount of Time to Collect Garbage	Python	Medium
2393	Count Strictly Increasing Subarrays	Python	Medium
2433	Find the Original Array of Prefix XOR	Python	Medium
2482	Difference Between Ones and Zeros in Row and Column	Python	Medium
2483	Minimum Penalty for a Shop	Python	Medium
2610	Convert an Array into a 2D Array with Conditions	Python	Medium
2616	Minimize the Maximum Difference of Pairs	Python	Medium
2618	Check if Object Instance of Class	TypeScript	Medium
2619	Array.prototype.last	JavaScript, TypeScript	Easy
2620	Counter	JavaScript, TypeScript	Easy
2621	Sleep	JavaScript, TypeScript	Easy
2622	Cache with Time Limit	JavaScript, TypeScript	Medium
2623	Memoize	JavaScript, TypeScript	Medium
2624	Snail Traversal	TypeScript	Medium
2625	Flatten Deeply Nested Array	JavaScript, TypeScript	Medium
2626	Array Reduce Transformation	JavaScript, TypeScript	Easy
2627	Debounce	JavaScript, TypeScript	Medium
2628	JSON Deep Equal	JavaScript, TypeScript	Medium
2629	Function Composition	JavaScript, TypeScript	Easy
2630	Memoize II	TypeScript	Hard
2631	Group By	JavaScript, TypeScript	Medium
2632	Curry	JavaScript, TypeScript	Medium
2633	Convert Object to JSON String	JavaScript, TypeScript	Medium
2634	Filter Elements from Array	JavaScript, TypeScript	Easy
2635	Apply Transform over Each Element in Array	JavaScript, TypeScript	Easy
2636	Promise Pool	JavaScript, TypeScript	Medium
2637	Promise Time Limit	JavaScript, TypeScript	Medium
2642	Design Graph with Shortest Path Calculator	Python	Hard
2648	Generate Fibonacci Sequence	TypeScript	Easy
2649	Nested Array Generator	TypeScript	Medium
2650	Design Cancellable Function	TypeScript	Hard
2665	Counter II	JavaScript, TypeScript	Easy
2666	Allow One Function Call	JavaScript, TypeScript	Easy
2667	Create Hello World Function	JavaScript, TypeScript	Easy
2675	Array of Objects to Matrix	TypeScript	Hard
2676	Throttle	JavaScript, TypeScript	Medium
2677	Chunk Array	JavaScript, TypeScript	Easy
2690	Infinite Method Object	TypeScript	Easy
2692	Make Object Immutable	TypeScript	Medium
2694	Event Emitter	JavaScript	Medium
2695	Array Wrapper	JavaScript	Easy
2703	Return Length of Arguments Passed	JavaScript	Easy
2704	To Be or Not To Be	JavaScript	Easy
2705	Compact Object	JavaScript	Medium
2706	Buy Two Chocolates	Python	Easy
2707	Extra Characters in a String	Python	Medium
2715	Execute Cancellable Function with Delay	JavaScript	Easy
2721	Execute Asynchronous Functions in Parallel	JavaScript	Medium
2722	Join Two Arrays by ID	JavaScript	Medium
2723	Add Two Promises	JavaScript	Easy
2724	Sort By	JavaScript	Easy
2725	Interval Cancellation	JavaScript	Easy
2726	Calculator with Method Chaining	JavaScript	Easy
2727	Is Object Empty	JavaScript	Easy
2742	Painting the Walls	Python	Hard
2762	Continuous Subarrays	Python	Medium
2778	Sum of Squares of Special Elements	Python	Easy
2784	Check if Array is Good	Python	Easy
2785	Sort Vowels in a String	Python	Medium
2788	Split Strings by Separator	Python	Easy
2789	Largest Element in an Array after Merge Operations	Python	Medium
2798	Number of Employees Who Met the Target	Python	Easy
2806	Account Balance after Rounded Purchase	Python	Easy
2807	Insert Greatest Common Divisors in Linked List	Python	Medium
2810	Faulty Keyboard	Python	Easy
2811	Check If It Is Possible to Split Array	Python	Medium
2824	Count Pairs Whose Sum Is Less Than Target	Python	Easy
2825	Make String A Subsequence Using Cyclic Increments	Python	Medium
2833	Furthest Point from Origin	Python	Easy
2834	Find the Minimum Possible Sum of a Beautiful Array	Python	Medium
2849	Determine if a Cell is Reachable at a Given Time	Python	Medium
2870	Minimum Number of Operations to Make Array Empty	Python	Medium

How to Use

Clone the repository:

git clone https://github.com/hogan.tech/leetcode-solutions.git

Choose a Problem:

Browse the folders to find the LeetCode problem you want to solve.

Select a Language:

Inside each problem folder, you'll find solutions in various programming languages. Choose the language you prefer.

Read the ReadMe:

Each problem folder contains a README file with a problem description, approach, and code explanation. Read this to understand the solution.

Explore the Code:

Open the code file to view the implementation. Study the code and adapt it as needed for your use case.

Run the Code:

You can run the code on your local machine to test and modify it as needed.

Contribute:

If you have a better solution or want to contribute in any way, feel free to submit a pull request.

Share Your Feedback:

Welcome feedback and suggestions. If you have any ideas to improve the solutions or find any errors, please let me know.

Happy coding! 🚀

By following these steps, users can easily navigate and utilize your LeetCode solutions repository for their coding needs.

leslovean / leetcode-solution Goto Github PK