CustomCC0-1.0#cp-tp3-0061400
Shortest Repeating Subsequence Cover
Summary
- •Phase 3 / string-period
- •Reasoning-first competitive programming drill
Problem Description
Given a string s of length n, find the length of the shortest substring t (t may repeat) such that s can be written as t concatenated some number of times (possibly with t truncated at end). Output the minimal length of t.
How to read this problem in plain language:
- This is a Phase 3 reasoning drill focused on string-period.
- Typical lenses to test first: string, periodicity, kmp.
- Constraints reminder: 1 ≤ lowercase string
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 ≤ lowercase string
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.
stringperiodicitykmpprefix-function