CustomCC0-1.0#cp-tp3-0201775
Lexicographical Array Jump
Summary
- •Phase 3 / array-jump
- •Reasoning-first competitive programming drill
Problem Description
Given an array of n integers, from index i you can jump to any index with a[i] < a[j]. Find the lex smallest sequence of jumps starting at index 1 that reaches the end, or report impossible.
How to read this problem in plain language:
- This is a Phase 3 reasoning drill focused on array-jump.
- Typical lenses to test first: array, jump, greedy.
- Constraints reminder: 1 ≤ ≤ 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 ≤ ≤ 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.
arrayjumpgreedylex-ordersegment-tree