CustomCC0-1.0#P0101800
Pairwise Minimum Path Sum
Summary
- •Phase 2 / Tree, Path Queries
- •Reasoning-first competitive programming drill
Problem Description
Given a connected undirected weighted tree of N nodes, for every unordered pair of nodes (u,v), find the minimum weight along the path from u to v. Output the sum over all pairs.
How to read this problem in plain language:
- This is a Phase 2 reasoning drill focused on Tree, Path Queries.
- Typical lenses to test first: tree, path, pairwise.
- Constraints reminder: 2 ≤ , 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
- •2 ≤ , 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.
treepathpairwisemin