Chapter 5
Stacks & Queues
4 topics in 3 parts
Key ideas
| Approach | Time Complexity | Auxiliary Space | Key Limitation |
|---|---|---|---|
| Brute Force Approach | O(N²) or O(2ᴺ) | O(1) / Minimal | Times out on large constraints ($N > 10^4$) |
| Optimal Approach | O(N) or O(N log N) | O(1) / O(N) | Requires sorted invariant or hash set lookup |
| Theoretical Lower Bound | Ω(N) | O(1) | Must inspect every element at least once |
All 4 topics in Stacks & Queues
Stacks
- Stack Data Structure (LIFO)
Queues
- Queue & Circular Queue
Stacks
- Monotonic Stack Pattern
- Balanced Parentheses Check