Few select Leetcode exercises in Kotlin.

Core patterns:

1. Two pointers
2. Sliding window
3. Prefix sum
4. Fast and slow pointers
5. Hashing
6. Reverse list
7. Stacks and queues
8. Trees
9. DFS and BFS
10. Graphs
11. Heaps
12. Binary search
13. Backtracking
14. Greedy algorithms
15. Dynamic programming