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 |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Easy](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/EasyGreen.svg) |
O(nlogn) |
O(1) |
Array, Hash Table |
2 |
Add Two Numbers |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(max(m,n)) |
O(1) |
Linked List, Math, Recursion |
5 |
Longest Palindromic Substring |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(n²) |
O(n²) |
String, DP |
20 |
Valid Parentheses |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Easy](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/EasyGreen.svg) |
O(n) |
O(n) |
String, Stack |
21 |
Merge Two Sorted Lists |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Easy](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/EasyGreen.svg) |
O(n) |
O(n) |
Linked List, Recursion |
23 |
Merge K Sorted Lists |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(nlogk) |
O(n) |
Linked List, Divide And Conquer, Priority Queue, Merge Sort |
42 |
Trapping Rain Water |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(n) |
O(1) |
Array, Two Pointers, DP, Stack |
127 |
Word Ladder |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(nm²) |
O(nm) |
BFS, Hash Table, String |
138 |
Copy List With Random Pointers |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(n) |
O(1) |
Hash Table, Linked List |
146 |
LRU Cache |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(1) |
O(1) |
Hash Table, Linked List, Design, Doubly Linked List |
200 |
Number Of Islands |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(mn) |
O(min(m,n)) |
Array, BFS, DFS, Matrix, Union Find |
295 |
Find Median From Data Stream |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(logn) |
O(n) |
Two Pointers, Design, Sorting, Priority Queue, Data Stream |
297 |
Serialize And Deserialize Binary Tree |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(n) |
O(n) |
String, Tree, Dfs, Bfs, Design, Binary Tree |
692 |
Top K Frequent Words |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(nlogn) |
O(n) |
Hash Table, String, Trie, Sorting, Priority Queue, Bucket Sort, Counting |
763 |
Partition Labels |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(n) |
O(n) |
Hash Table, Two Pointers, String, Greedy |
819 |
Most Common Word |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Easy](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/EasyGreen.svg) |
O(n+m) |
O(n+m) |
Hash Table, String |
937 |
Reorder Data In Log Files |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Easy](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/EasyGreen.svg) |
O(nlogn) |
O(n) |
Array, String, Sorting |
973 |
K Closest Points To Origin |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(nlogn) |
O(n) |
Array, Math, Divide And Conquer, Geometry, Sorting, Priority Queue, Quick Select |
994 |
Rotting Oranges |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Medium](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/MediumBlue.svg) |
O(mn) |
O(mn) |
Array, BFS, Matrix |
1192 |
Critical Connections In A Network |
![Solution](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/github.svg) |
|
![Hard](https://raw.githubusercontent.com/AnanyaBhatKinila/Leetcode/main/images/HardRed.svg) |
O(E+V) |
O(E+V) |
DFS, Graph, Biconnected Components |