CustomCC0-1.0#p0111650
Colorful Range Queries
Summary
- •Phase 1 / mo, sqrt_decomp
- •Reasoning-first competitive programming drill
Problem Description
You are given an array of length n where each element is a color (integer 1..c). You must process q queries of the form (l, r): report the number of distinct colors in a[l..r].
How to read this problem in plain language:
- This is a Phase 1 reasoning drill focused on mo, sqr.
- Typical lenses to test first: mo's algorithm, range query, frequency.
- Constraints reminder: 1 ≤ n, , 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 ≤ n, , 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.
mo's algorithmrange queryfrequency