LeetCode

Solutions for LeetCode

Algorithms

#	Title	Solution	Difficulty	Topic	Tag
1	Two Sum	Python	Easy	Array
4	Median of Two Sorted Arrays	Swift	Hard	Array	Binary Search
11	Container With Most Water	Swift	Medium	Array	Greedy, Two Pointers
15	3Sum	Swift, Python	Medium	Array	Two pointers
31	Next Permutation	Python	Medium	Array
42	Trapping Rain Water	Python	Hard	Array
53	Maximum Subarray	Python	Medium	Array	Dynamic Programming
56	Merge Intervals	Python	Medium	Array	Sorting
84	Largest Rectangle in Histogram	Swift	Hard	Array	Monotonic Stack
121	Best Time to Buy and Sell Stock	Python	Easy	Array	Dynamic Programming
122	Best Time to Buy and Sell Stock II	Swift	Medium	Array	Greedy
123	Best Time to Buy and Sell Stock III	Swift	Hard	Array
134	Gas Station	Swift	Medium	Array	Greedy
167	Two Sum II - Input Array Is Sorted	Swift	Medium	Array	Two Pointers
169	Majority Element	Python	Easy	Array
200	Number of Islands	Swift	Medium	Array	Breadth-first search
217	Contains Duplicate	Java	Easy	Array
221	Maximal Square	Swift	Medium	Array	Dynamic Programming
283	Move Zeroes	Java	Easy	Array
322	Coin Change	Swift	Medium	Array	Dynamic Programming
349	Intersection of Two Arrays	Swift	Easy	Array
350	Intersection of Two Arrays II	Swift	Easy	Array
416	Partition Equal Subset Sum	Python	Medium	Array	Dynamic Programming
447	Number of Boomerangs	Swift	Medium	Array
453	Minimum Moves to Equal Array Elements	Swift	Medium	Array
455	Assign Cookies	Swift	Easy	Array
463	Island Perimeter	Swift	Easy	Array
500	Keyboard Row	Swift	Easy	Array
518	Coin Change II	Swift	Medium	Array	Dynamic Programming, Knapsack
532	K-diff Pairs in an Array	Python	Medium	Array
560	Subarray Sum Equals K	Python	Medium	Array
561	Array Partition	Swift	Easy	Array	Greedy
739	Daily Temperatures	Python	Medium	Array	Stack
811	Subdomain Visit Count	Python	Medium	Array
923	3Sum With Multiplicity	Python	Medium	Array
1167	Minimum Cost to Connect Sticks	Swift	Medium	Array	Heap, Priority Queue
3	Longest Substring Without Repeating Characters	Swift	Medium	String	Sliding Window
5	Longest Palindromic Substring	Python	Medium	String
13	Roman to Integer	Python	Easy	String
14	Longest Common Prefix	Python	Easy	String
20	Valid Parentheses	Python	Easy	String	Stack
22	Generate Parentheses	Python	Medium	String
316	Remove Duplicate Letters	Swift, Python	Medium	String	Stack, Greedy
344	Reverse String	Java	Easy	String
383	Ransom Note	Java	Easy	String
387	First Unique Character in a String	Swift	Easy	String
389	Find the Difference	Swift	Easy	String
409	Longest Palindrome	Swift	Easy	String
557	Reverse Words in a String III	Swift	Easy	String
647	Palindromic Substrings	Python	Medium	String
657	Robot Return to Origin	Swift	Easy	String
1143	Longest Common Subsequence	Python	Medium	String	Dynamic Programming
1249	Minimum Remove to Make Valid Parentheses	Python	Medium	String	Stack
1668	Maximum Repeating Substring	Python	Easy	String	KMP
2	Add Two Numbers	Python	Medium	Linked List
19	Remove Nth Node From End of List	Swift	Medium	Linked List
141	Linked List Cycle	Python	Easy	Linked List
142	Linked List Cycle II	Python	Medium	Linked List
206	Reverse Linked List	Java	Easy	Linked List
237	Delete Node in a Linked List	Java	Medium	Linked List
146	LRU Cache	Python	Medium	Hash Table
242	Valid Anagram	Java	Easy	Hash Table
94	Binary Tree Inorder Traversal	Swift	Easy	Tree	Depth-first search
100	Same Tree	Python	Easy	Tree
104	Maximum Depth of Binary Tree	Python	Easy	Tree
144	Binary Tree Preorder Traversal	Swift	Easy	Tree	Depth-first search
145	Binary Tree Postorder Traversal	Swift	Easy	Tree	Depth-first search
226	Invert Binary Tree	Java	Easy	Tree
404	Sum of Left Leaves	Swift	Easy	Tree
617	Merge Two Binary Trees	Swift	Easy	Tree
669	Trim a Binary Search Tree	Swift	Medium	Tree	Binary Search Tree
136	Single Number	Python	Easy	Bit Manipulation
137	Single Number II	Python	Medium	Bit Manipulation
401	Binary Watch	Swift	Easy	Bit Manipulation
461	Hamming Distance	Swift	Easy	Bit Manipulation
476	Number Complement	Swift	Easy	Bit Manipulation
7	Reverse Integer	Python	Medium	Math
171	Excel Sheet Column Number	Python	Easy	Math
258	Add Digits	Java	Easy	Math
292	Nim Game	Java	Easy	Math
371	Sum of Two Integers	Java	Medium	Math
412	FizzBuzz	Java	Easy	Math
415	Add Strings	Swift	Easy	Math
535	Encode and Decode TinyURL	Swift	Medium	System Design

Database

#	Title	Solution	Difficulty
175	Combine Two Tables	SQL	Easy
176	Second Highest Salary	SQL	Medium
177	Nth Highest Salary	SQL	Medium
178	Rank Scores	SQL	Medium
180	Consecutive Numbers	SQL	Medium
181	Employees Earning More Than Their Managers	SQL	Easy
182	Duplicate Emails	SQL	Easy
183	Customers Who Never Order	SQL	Easy
184	Department Highest Salary	SQL	Medium
185	Department Top Three Salaries	SQL	Hard
196	Delete Duplicate Emails	SQL	Easy
197	Rising Temperature	SQL	Easy
262	Trips and Users	SQL	Hard
595	Big Countries	SQL	Easy
596	Classes More Than 5 Students	SQL	Easy
601	Human Traffic of Stadium	SQL	Hard
620	Not Boring Movies	SQL	Easy
626	Exchange Seats	SQL	Medium
627	Swap Salary	SQL	Easy

Shell

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

Concurrency

#	Title	Solution	Difficulty
1114	Print in Order	Python	Easy
1195	Fizz Buzz Multithreaded	Python	Medium