CustomCC0-1.0#P016-8201700
K-Radius Tree Value Propagation
Summary
- •Phase 5 / tree/distance/propagation
- •Reasoning-first competitive programming drill
Problem Description
Given a tree with N nodes (1-based) and node values V[i], each node propagates its value to all nodes within distance K. Compute the sum at each node after all propagations.
How to read this problem in plain language:
- This is a Phase 5 reasoning drill focused on tree/distance/propagation.
- Typical lenses to test first: tree, bfs, distance.
- Constraints reminder: 1 ≤ 0 ≤ 1 ≤ V[i] ≤ 10^4
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 ≤ 0 ≤ 1 ≤ V[i] ≤ 10^4
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.
treebfsdistance