CustomCC0-1.0#cptp0192100
Weighted Unique Substring Sum
Summary
- •Phase 5 / suffix_automaton, string_hashing
- •Reasoning-first competitive programming drill
Problem Description
Given a string S of length n (consisting of lowercase letters), and an array of n integer weights wi, compute the sum over all unique substrings of S, where each substring's value is the sum of wi for its positions.
How to read this problem in plain language:
- This is a Phase 5 reasoning drill focused on suffi, strin.
- Typical lenses to test first: strings, suffix-automaton, hashing.
- Constraints reminder: 1 ≤ , ≤ 1e6
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 ≤ , ≤ 1e6
Analysis
Key Insight
The goal is to force explicit intermediate reasoning before revealing more.
stringssuffix-automatonhashing