Foundations
Core topics, one practice step at a time: Hash Map, Sliding Window, Two Pointers, Stack, Linked List, Greedy, Prefix Sum.
- 1
Hash Map — O(1) lookups
- 2
Sliding Window — scan contiguous subarrays
- 3
Two Pointers — scan from both ends
- 4
Stack — last in, first out
- 5
Linked List — node linked to node
- 6
Greedy — pick the best option locally
- 7
Prefix Sum — fast range sums
- 8
Review & practice