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CustomCC0-1.0#cp-tp3-0081500

Equal Height Pyramid

Thinking Mode

Summary

  • •Phase 3 / greedy-operations
  • •Reasoning-first competitive programming drill

Problem Description

Given n columns with positive integer heights, you may decrease the height of any column to match that of a neighbor. What is the minimum number of operations needed to make all columns the same height? How to read this problem in plain language: - This is a Phase 3 reasoning drill focused on greedy-operations. - Typical lenses to test first: greedy, array, operations. - Constraints reminder: 1 ≤ n≤2e5; 1 ≤ hi​≤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

  • •
    1 ≤ n≤2e5; 1 ≤ hi​≤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.

greedyarrayoperations
greedyarrayoperations