CustomCC0-1.0#P015-1642100
Unique Divisor Path Sum
Summary
- •Phase 5 / prefix_sum/divisor/unique
- •Reasoning-first competitive programming drill
Problem Description
Given an array A of N integers, find the length of the longest contiguous subarray such that the sum of the subarray is divisible by exactly one element in that subarray.
How to read this problem in plain language:
- This is a Phase 5 reasoning drill focused on prefi/divisor/unique.
- Typical lenses to test first: prefix sum, divisibility, array.
- Constraints reminder: 1 ≤ 1 ≤ A[i] ≤ 10^6
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 ≤ 1 ≤ A[i] ≤ 10^6
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.
prefix sumdivisibilityarray