dennyhong96 / fe-dsa

Leetcode problem solutions implemented in TypeScript

Data structures and Algorithms in TypeScript

Data Structures

0. String
1. Array
2. Hash Table
3. Linked List
4. Stacks & Queues
5. Trees
6. Graphs

Algorithms

7. Recursion
8. Sorting
9. Searching
10. Dynamic Programming

Patterns

14. Two Pointers
15. Sliding Window
16. Matrix Treversal
17. Arrays
18. LinkedList
19. Tree BFS Treversal
20. Tree DFS Treversal
21. Binary Search

General Tips

• If input array is sorted then
  • Two pointers
  • Sliding window
  • Binary search
• If given a tree then
  • DFS
  • BFS
• If given a linked list then
  • Offset pointers
  • Fast & slow pointers
• If recursion is banned then
  • Stack
• If must solve in-place then
  • Swap corresponding values
  • Store one or more different values in the same pointer
• If asked for common strings then
  • Map
  • Trie
• Else
  • Map/Set for O(1) time & O(n) space
  • Sort input for O(nlogn) time and O(1) space