Leetcode

Leetcode Questions Practice

Click on difficulty buttons (Easy, Medium, Hard) or Tags or company to filter that category problems only.

#	Title	Sol	Companies	Difficulty	Time	Space	Tags
1	Two Sum				O(nlogn)	O(1)	Array, Hash Table
2	Add Two Numbers				O(max(m,n))	O(1)	Linked List, Math, Recursion
5	Longest Palindromic Substring				O(n²)	O(n²)	String, DP
20	Valid Parentheses				O(n)	O(n)	String, Stack
21	Merge Two Sorted Lists				O(n)	O(n)	Linked List, Recursion
23	Merge K Sorted Lists				O(nlogk)	O(n)	Linked List, Divide And Conquer, Priority Queue, Merge Sort
42	Trapping Rain Water				O(n)	O(1)	Array, Two Pointers, DP, Stack
127	Word Ladder				O(nm²)	O(nm)	BFS, Hash Table, String
138	Copy List With Random Pointers				O(n)	O(1)	Hash Table, Linked List
146	LRU Cache				O(1)	O(1)	Hash Table, Linked List, Design, Doubly Linked List
200	Number Of Islands				O(mn)	O(min(m,n))	Array, BFS, DFS, Matrix, Union Find
295	Find Median From Data Stream				O(logn)	O(n)	Two Pointers, Design, Sorting, Priority Queue, Data Stream
297	Serialize And Deserialize Binary Tree				O(n)	O(n)	String, Tree, Dfs, Bfs, Design, Binary Tree
692	Top K Frequent Words				O(nlogn)	O(n)	Hash Table, String, Trie, Sorting, Priority Queue, Bucket Sort, Counting
763	Partition Labels				O(n)	O(n)	Hash Table, Two Pointers, String, Greedy
819	Most Common Word				O(n+m)	O(n+m)	Hash Table, String
937	Reorder Data In Log Files				O(nlogn)	O(n)	Array, String, Sorting
973	K Closest Points To Origin				O(nlogn)	O(n)	Array, Math, Divide And Conquer, Geometry, Sorting, Priority Queue, Quick Select
994	Rotting Oranges				O(mn)	O(mn)	Array, BFS, Matrix
1192	Critical Connections In A Network				O(E+V)	O(E+V)	DFS, Graph, Biconnected Components