CustomCC0-1.0#cp0191500
Subset Sum Parity Count
Summary
- •Phase 4 / dp, parity, combinatorics
- •Reasoning-first competitive programming drill
Problem Description
Given n positive integers, for each i from 1 to n, compute the number of subsets of size i whose sum is even.
How to read this problem in plain language:
- This is a Phase 4 reasoning drill focused on dp, parity, combinatorics.
- Typical lenses to test first: dp, combinatorics, parity.
- Constraints reminder: 1 ≤ 1 ≤
Mini examples for mental simulation:
1) Boundary example: Describe why this case is tricky. Explain expected behavior and why naive logic may fail.
2) Adversarial example: Adversarial case where naive greedy/local decision looks correct but fails globally.
Lite-mode writing target:
- Write 1~2 observations that shrink the search space.
- Name one final algorithm and state target complexity explicitly.
- Validate with at least 2 edge cases and one hand simulation.
Constraints
- •1 ≤ 1 ≤
Analysis
Key Insight
Use this hint to refine your reasoning. This step should reduce search space or formalize correctness. State why this insight changes your algorithm choice.
dpcombinatoricsparity