LeetCode

https://leetcode.com

June LeetCoding Challenge

Click here for problem descriptions.

Solutions in various programming languages are provided. Enjoy it.

1. Invert Binary Tree: Tree Traversal
2. Delete Node in a Linked List: Linked List
3. Two City Scheduling: DP

May LeetCoding Challenge

Click here for problem descriptions.

Solutions in various programming languages are provided. Enjoy it.

1. First Bad String: Binary search.
2. Jewels and Stones: Hash Table
3. Ransom Note: Hash Table
4. Number Complement: Bitwise Manipulation
5. First Unique Character In a String: Hash Table
6. Majority Element: Ad hoc
7. Cousins in Binary Tree: BFS / Recursion
8. Check if it is straight line: Cross Product
9. Valid Perfect Square: Math
10. Find the Town Judge: Graph Theory
11. Flood Fill: BFS
12. Single Element In a Sorted Array: Binary Search
13. Remove K Digits: Greedy
14. Implement Trie: Trie
15. Maximum Sum Circular Subarray: DP
16. Odd Even Linked List: Linked List
17. Find All Anagrams in a String: Sliding window + Hash Table
18. Permutation In String: Sliding window + Hash Table
19. Online Stock Span: DP
20. Kth-Smallest-Element-In-A-BST: BST
21. Count Square Submatrices with All Ones: DP
22. Sort Characters By Frequency: Hash Table
23. Interval List Intersections: Two Pointers
24. Construct Binary Search Tree from Preorder Traversal: Binary Search Tree
25. Uncrossed Lines: DP
26. Contiguous Array: Hash Table
27. Possible Bipartition: Bipartite Graph
28. Counting Bits: Math
29. Course Schedule: Topological Sort
30. K Closest Points to Origin: Priority_queue, Sort
31. Edit Distance: DP

30-Day (April) LeetCoding Challenge

Click here for problem descriptions.

1. Single Number: Bitwise Manipulation
2. Happy Number: Implementation
3. Maximum Subarray: DP
4. Move Zeros: Two pointers
5. Best Time to Buy and Sell Stock II: Greedy
6. Group Anagrams: Hash Table