Problem-solving Practice Log

Pattern map

Arrays and hashing, two pointers, sliding windows, binary search, trees and graphs, heaps, backtracking, and dynamic programming.

Per-problem log

Explain without notes

1. Clarify constraints and edge cases.
2. Establish a baseline and justify improvements.
3. Explain the invariant and correctness.
4. Check empty inputs, duplicates, and large cases.
5. Record the cause of mistakes; solve from scratch next time.

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