CustomCC0-1.0#P0021800
Tree Rerooting Value
Summary
- •Phase 2 / Tree DP, Rerooting
- •Reasoning-first competitive programming drill
Problem Description
Given a tree with N nodes and a value V[i] for each node, reroot the tree at every node and, for each rerooted tree, compute the sum over all nodes of their depth times their value. Output the maximum such sum over all possible roots.
How to read this problem in plain language:
- This is a Phase 2 reasoning drill focused on Tree DP, Rerooting.
- Typical lenses to test first: tree, rerooting, dp.
- Constraints reminder: 2 ≤ , 0 ≤ V[i] ≤ 1e9
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 ≤ , 0 ≤ V[i] ≤ 1e9
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.
treererootingdp