LeetCode Solution

Cracking the LeetCode with multiple programming languages How do I choose the solution?

1. Choose the solution with the best time complexity and space complexity from the official solutions.
2. If the best time complexity and space complexity solutions are different, choose the best solution from each one.
3. If there are no official solutions, choose the best solution from the submissions for each language. These best solutions are not necessarily the ones with the best time complexity and space complexity but instead are selected based on the readability of the solution. Overly complex and tricky solutions will not be selected.

Algorithms

Number	Title	Difficulty	Solution	Golang	JavaScript	Kotlin	PHP	Python	Rust	Swift
1	Two Sum	Easy	✅	✅	✅	✅	✅	✅	✅	✅
2	Add Two Numbers	Medium	✅	✅	✅	✅	✅	✅	✅	✅
3	Longest Substring Without Repeating Characters	Medium	✅	✅	✅	✅	✅	✅	✅	✅
4	Median of Two Sorted Arrays	Hard		✅	✅	✅	✅	✅	✅	✅
5	Longest Palindromic Substring	Medium	✅	✅	✅			✅
6	ZigZag Conversion	Medium	✅	✅	✅	✅		✅		✅
7	Reverse Integer	Easy	✅	✅	✅	✅	✅	✅	✅	✅
8	String to Integer (atoi)	Medium		✅	✅	✅		✅		✅
9	Palindrome Number	Easy		✅	✅	✅		✅		✅
10	Regular Expression Matching	Hard		✅	✅	✅		✅		✅
11	Container With Most Water	Medium	✅	✅	✅	✅	✅	✅		✅
12	Integer to Roman	Medium		✅	✅	✅		✅		✅
13	Roman to Integer	Easy		✅	✅	✅		✅		✅
14	Longest Common Prefix	Easy	✅	✅	✅	✅	✅	✅		✅
15	3Sum	Medium		✅	✅	✅		✅		✅
16	3Sum Closest	Medium		✅	✅	✅		✅		✅
17	Letter Combinations of a Phone Number	Medium		✅	✅	✅		✅		✅
18	4Sum	Medium		✅	✅	✅		✅		✅
19	Remove Nth Node From End of List	Medium	✅	✅	✅	✅	✅	✅		✅
20	Valid Parentheses	Easy		✅	✅	✅		✅		✅
21	Merge Two Sorted Lists	Easy	✅	✅	✅	✅	✅	✅		✅
22	Generate Parentheses	Medium		✅	✅	✅		✅		✅
23	Merge k Sorted Lists	Hard		✅	✅	✅		✅		✅
24	Swap Nodes in Pairs	Medium		✅	✅	✅		✅		✅
25	Reverse Nodes in k-Group	Hard		✅	✅	✅		✅		✅
26	Remove Duplicates from Sorted Array	Easy	✅	✅	✅	✅	✅	✅	✅	✅
27	Remove Element	Easy	✅	✅	✅	✅	✅	✅	✅	✅
28	Implement strStr()	Easy		✅	✅	✅	✅	✅		✅
29	Divide Two Integers	Medium		✅	✅	✅		✅		✅
30	Substring with Concatenation of All Words	Hard		✅	✅	✅		✅		✅
31	Next Permutation	Medium	✅	✅	✅	✅	✅	✅		✅
32	Longest Valid Parentheses	Hard		✅	✅	✅		✅		✅
39	Combination Sum	Medium		✅	✅			✅
46	Permutations	Medium		✅	✅	✅		✅		✅
54	Spiral Matrix	Medium		✅	✅	✅		✅		✅
59	Spiral Matrix II	Medium	✅	✅	✅			✅
61	Rotate List	Medium	✅	✅	✅	✅	✅	✅		✅
66	Plus One	Easy	✅	✅	✅	✅	✅	✅		✅
67	Add Binary	Easy	✅	✅	✅		✅	✅
70	Climbing Stairs	Easy		✅	✅	✅		✅		✅
74	Search a 2D Matrix	Medium	✅	✅	✅	✅	✅	✅	✅	✅
75	Sort Colors	Medium	✅	✅	✅	✅		✅	✅	✅
78	Subsets	Medium	✅	✅	✅	✅	✅	✅	✅	✅
79	Word Search	Medium		✅	✅	✅		✅		✅
81	Search in Rotated Sorted Array II	Medium	✅	✅	✅		✅	✅
88	Merge Sorted Array	Easy	✅	✅	✅			✅
94	Binary Tree Inorder Traversal	Medium		✅	✅	✅		✅		✅
99	Recover Binary Search Tree	Medium	✅		✅			✅
104	Maximum Depth of Binary Tree	Easy		✅	✅	✅		✅		✅
115	Distinct Subsequences	Hard		✅	✅	✅		✅		✅
118	Pascal's Triangle	Easy	✅	✅	✅	✅	✅	✅	✅	✅
119	Pascal's Triangle II	Easy	✅	✅	✅	✅	✅	✅		✅
121	Best Time to Buy and Sell Stock	Easy		✅	✅	✅		✅		✅
127	Word Ladder	Hard		✅	✅	✅		✅		✅
129	Sum Root to Leaf Numbers	Medium		✅	✅	✅		✅		✅
130	Surrounded Regions	Medium		✅	✅	✅		✅		✅
134	Gas Station	Medium		✅	✅	✅		✅		✅
136	Single Number	Easy		✅	✅	✅	✅	✅	✅	✅
138	Copy List with Random Pointer	Medium	✅	✅	✅			✅
141	Linked List Cycle	Easy	✅	✅	✅	✅	✅	✅		✅
142	Linked List Cycle II	Medium	✅	✅	✅	✅	✅	✅		✅
147	Insertion Sort List	Medium	✅	✅	✅	✅	✅	✅	✅	✅
151	Reverse Words in a String	Medium	✅	✅	✅		✅	✅
160	Intersection of Two Linked Lists	Easy	✅	✅	✅	✅	✅	✅		✅
167	Two Sum II - Input Array Is Sorted	Medium	✅	✅	✅	✅	✅	✅	✅	✅
173	Binary Search Tree Iterator	Medium	✅	✅	✅		✅	✅		✅
189	Rotate Array	Medium	✅	✅	✅		✅	✅		✅
198	House Robber	Medium	✅	✅	✅	✅	✅	✅		✅
203	Remove Linked List Elements	Easy	✅	✅	✅	✅	✅	✅		✅
206	Reverse Linked List	Easy	✅	✅	✅	✅	✅	✅		✅
209	Minimum Size Subarray Sum	Medium	✅		✅			✅
230	Kth Smallest Element in a BST	Medium	✅	✅	✅			✅
234	Palindrome Linked List	Easy	✅	✅	✅	✅	✅	✅		✅
237	Delete Node in a Linked List	Easy		✅	✅	✅		✅		✅
258	Add Digits	Easy		✅	✅	✅		✅		✅
279	Perfect Squares	Medium		✅	✅	✅		✅		✅
282	Expression Add Operators	Hard		✅	✅	✅		✅		✅
283	Move Zeroes	Easy	✅	✅	✅	✅	✅	✅		✅
284	Peeking Iterator	Medium	✅		✅			✅
287	Find the Duplicate Number	Medium	✅	✅	✅	✅	✅	✅	✅	✅
289	Game of Life	Medium	✅	✅	✅			✅
290	Word Pattern	Easy		✅	✅	✅		✅		✅
309	Best Time to Buy and Sell Stock with Cooldown	Medium		✅	✅	✅		✅		✅
312	Burst Balloons	Hard		✅	✅	✅		✅		✅
328	Odd Even Linked List	Medium	✅	✅	✅	✅	✅	✅		✅
344	Reverse String	Easy	✅	✅	✅	✅	✅	✅	✅	✅
347	Top K Frequent Elements	Medium	✅					✅
387	First Unique Character in a String	Easy	✅	✅	✅	✅	✅	✅		✅
389	Find the Difference	Easy		✅	✅	✅		✅		✅
402	Remove K Digits	Medium		✅	✅	✅		✅		✅
410	Split Array Largest Sum	Hard	✅	✅	✅	✅		✅		✅
412	Fizz Buzz	Easy	✅	✅	✅			✅
414	Third Maximum Number	Easy	✅	✅	✅			✅
430	Flatten a Multilevel Doubly Linked List	Medium	✅	✅	✅			✅
442	Find All Duplicates in an Array	Medium		✅	✅	✅		✅		✅
448	Find All Numbers Disappeared in an Array	Easy	✅	✅	✅	✅	✅	✅		✅
452	Minimum Number of Arrows to Burst Balloons	Medium		✅	✅	✅		✅		✅
463	Island Perimeter	Easy		✅	✅	✅		✅		✅
485	Max Consecutive Ones	Easy	✅	✅	✅	✅	✅	✅	✅	✅
487	Max Consecutive Ones II	Medium	✅	✅	✅	✅	✅	✅		✅
498	Diagonal Traverse	Medium	✅	✅	✅		✅	✅
504	Base 7	Easy		✅	✅			✅
520	Detect Capital	Easy		✅	✅	✅		✅		✅
532	K-diff Pairs in an Array	Medium		✅	✅	✅		✅		✅
538	Convert BST to Greater Tree	Medium	✅	✅	✅			✅
557	Reverse Words in a String III	Easy	✅	✅	✅	✅	✅	✅		✅
560	Subarray Sum Equals K	Medium	✅	✅	✅	✅	✅	✅	✅	✅
561	Array Partition I	Easy		✅	✅	✅	✅	✅	✅	✅
567	Permutation in String	Medium	✅	✅	✅			✅
605	Can Place Flowers	Easy		✅	✅	✅		✅		✅
669	Trim a Binary Search Tree	Medium	✅	✅	✅	✅	✅	✅	✅	✅
680	Valid Palindrome II	Easy	✅	✅	✅	✅	✅	✅		✅
682	Baseball Game	Easy	✅	✅	✅			✅
698	Partition to K Equal Sum Subsets	Medium		✅	✅			✅		✅
700	Search in a Binary Search Tree	Easy	✅	✅	✅	✅	✅	✅	✅	✅
701	Insert into a Binary Search Tree	Medium		✅	✅	✅		✅		✅
703	Kth Largest Element in a Stream	Easy	✅	✅	✅	✅	✅	✅	✅	✅
705	Design HashSet	Easy	✅		✅		✅	✅
707	Design Linked List	Medium	✅	✅	✅			✅		✅
708	Insert into a Sorted Circular Linked List	Medium	✅	✅	✅	✅	✅	✅		✅
724	Find Pivot Index	Easy	✅	✅	✅	✅	✅	✅		✅
725	Split Linked List in Parts	Medium		✅	✅	✅		✅		✅
740	Delete and Earn	Medium	✅	✅	✅			✅
746	Min Cost Climbing Stairs	Easy	✅	✅	✅	✅	✅	✅		✅
747	Largest Number At Least Twice of Others	Easy		✅	✅	✅	✅	✅		✅
763	Partition Labels	Medium	✅	✅	✅	✅		✅		✅
764	Largest Plus Sign	Medium		✅	✅	✅		✅		✅
782	Transform to Chessboard	Hard		✅	✅			✅
848	Shifting Letters	Medium		✅	✅	✅		✅		✅
875	Koko Eating Bananas	Medium		✅	✅	✅		✅		✅
876	Middle of the Linked List	Easy	✅	✅	✅	✅	✅	✅		✅
881	Boats to Save People	Medium	✅	✅	✅	✅	✅	✅	✅	✅
882	Reachable Nodes In Subdivided Graph	Hard		✅	✅			✅		✅
897	Increasing Order Search Tree	Easy	✅	✅	✅	✅	✅	✅		✅
905	Sort Array By Parity	Easy	✅	✅	✅	✅	✅	✅		✅
917	Reverse Only Letters	Easy		✅	✅	✅		✅		✅
922	Sort Array By Parity II	Easy		✅	✅	✅		✅		✅
923	3Sum With Multiplicity	Medium	✅	✅	✅	✅		✅		✅
929	Unique Email Addresses	Easy		✅	✅	✅		✅		✅
941	Valid Mountain Array	Easy		✅	✅	✅		✅		✅
977	Squares of a Sorted Array	Easy	✅	✅	✅	✅	✅	✅	✅	✅
978	Longest Turbulent Subarray	Medium		✅	✅	✅		✅		✅
980	Unique Paths III	Hard		✅	✅	✅		✅		✅
991	Broken Calculator	Medium	✅	✅	✅	✅	✅	✅	✅	✅
993	Cousins in Binary Tree	Easy		✅	✅	✅		✅		✅
1007	Minimum Domino Rotations For Equal Row	Medium	✅	✅	✅	✅	✅	✅		✅
1008	Construct Binary Search Tree from Preorder Traversal	Medium		✅	✅	✅		✅		✅
1029	Two City Scheduling	Medium	✅	✅	✅	✅	✅	✅	✅	✅
1046	Last Stone Weight	Easy	✅	✅	✅		✅	✅
1051	Height Checker	Easy		✅	✅	✅	✅	✅	✅	✅
1089	Duplicate Zeros	Easy	✅	✅	✅	✅	✅	✅		✅
1099	Two Sum Less Than K	Easy	✅	✅	✅		✅	✅
1143	Longest Common Subsequence	Medium		✅	✅	✅		✅		✅
1189	Maximum Number of Balloons	Easy		✅	✅	✅		✅		✅
1239	Maximum Length of a Concatenated String with Unique Characters	Medium		✅	✅	✅		✅		✅
1260	Shift 2D Grid	Easy	✅	✅	✅	✅	✅	✅		✅
1275	Find Winner on a Tic Tac Toe Game	Easy		✅	✅	✅		✅		✅
1293	Shortest Path in a Grid with Obstacles Elimination	Hard		✅	✅	✅		✅		✅
1295	Find Numbers with Even Number of Digits	Easy		✅	✅	✅	✅	✅	✅	✅
1299	Replace Elements with Greatest Element on Right Side	Easy		✅	✅	✅	✅	✅	✅	✅
1328	Break a Palindrome	Medium		✅	✅	✅		✅		✅
1342	Number of Steps to Reduce a Number to Zero	Easy	✅	✅	✅	✅		✅		✅
1346	Check If N and Its Double Exist	Easy		✅	✅	✅	✅	✅	✅	✅
1480	Running Sum of 1d Array	Easy	✅	✅	✅	✅	✅	✅	✅	✅
1629	Slowest Key	Easy		✅	✅	✅		✅		✅
1663	Smallest String With A Given Numeric Value	Medium		✅	✅	✅		✅		✅
1672	Richest Customer Wealth	Easy	✅	✅	✅	✅	✅	✅	✅	✅
1991	Find the Middle Index in Array	Easy		✅	✅	✅	✅	✅	✅	✅

Concurrency

Number	Title	Difficulty	Solution	Python
1114	Print in Order	Easy	✅	✅
1115	Print FooBar Alternately	Medium		✅
1116	Print Zero Even Odd	Medium		✅
1117	Building H2O	Medium		✅
1188	Design Bounded Blocking Queue	Medium		✅
1195	Fizz Buzz Multithreaded	Medium		✅
1226	The Dining Philosophers	Medium		✅
1242	Web Crawler Multithreaded	Medium
1279	Traffic Light Controlled Intersection	Easy

Database

Number	Title	Difficulty	Solution	MySQL
175	Combine Two Tables	Easy	✅	✅
176	Second Highest Salary	Medium	✅	✅
177	Nth Highest Salary	Medium		✅
178	Rank Scores	Medium		✅
180	Consecutive Numbers	Medium	✅	✅
181	Employees Earning More Than Their Managers	Easy	✅	✅
182	Duplicate Emails	Easy	✅	✅
183	Customers Who Never Order	Easy	✅	✅
184	Department Highest Salary	Medium	✅	✅
185	Department Top Three Salaries	Hard	✅	✅
196	Delete Duplicate Emails	Easy	✅	✅
197	Rising Temperature	Easy	✅	✅
262	Trips and Users	Hard		✅
511	Game Play Analysis I	Easy	✅	✅
584	Find Customer Referee	Easy	✅	✅
586	Customer Placing the Largest Number of Orders	Easy	✅	✅
595	Big Countries	Easy	✅	✅
596	Classes More Than 5 Students	Easy	✅	✅
601	Human Traffic of Stadium	Hard	✅	✅
607	Sales Person	Easy	✅	✅
620	Not Boring Movies	Easy	✅	✅
626	Exchange Seats	Medium	✅	✅
627	Swap Salary	Easy	✅	✅
1050	Actors and Directors Who Cooperated At Least Three Times	Easy		✅
1148	Article Views I	Easy		✅
1158	Market Analysis I	Medium		✅
1179	Reformat Department Table	Easy		✅
1407	Top Travellers	Easy		✅
1581	Customer Who Visited but Did Not Make Any Transactions	Easy		✅
1693	Daily Leads and Partners	Easy		✅
1729	Find Followers Count	Easy		✅
1757	Recyclable and Low Fat Products	Easy		✅
1873	Calculate Special Bonus	Easy		✅
1965	Employees With Missing Information	Easy		✅

Shell

Number	Title	Difficulty	Solution	Bash
192	Word Frequency	Medium		✅
193	Valid Phone Numbers	Easy		✅
194	Transpose File	Medium		✅
195	Tenth Line	Easy		✅