CustomCC0-1.0#cp001-8931500
Modulo K Equal Frequency
Summary
- •Phase 5 / arrays, greedy, math
- •Reasoning-first competitive programming drill
Problem Description
Given an array of n integers and an integer k, find the minimal number of elements to remove so that, for every residue r (0 <= r < k), the count of numbers congruent to r modulo k are all equal.
How to read this problem in plain language:
- This is a Phase 5 reasoning drill focused on arrays, greedy, math.
- Typical lenses to test first: arrays, greedy, frequency.
- Constraints reminder: 1 <= n <= 2*10^5, 2 <= k <= min(100, n), 1 <= ai <= 10^9
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 <= 2*10^5, 2 <= k <= min(100, n), 1 <= ai <= 10^9
Analysis
Key Insight
The goal is to force explicit intermediate reasoning before revealing more.
arraysgreedyfrequencymodulo