CustomCC0-1.0#ct-p4-022050
Offline Greater-Than Queries
Summary
- •Phase 4 / fenwick-offline
- •Reasoning-first competitive programming drill
Problem Description
For each query (l,r,x), count numbers > x in subarray a[l..r]. Your submission must justify algorithm choice, prove correctness, and test adversarial edge cases.
How to read this problem in plain language:
- This is a Phase 4 reasoning drill focused on fenwick-offline.
- Typical lenses to test first: offline, fenwick, sorting.
- Constraints reminder: n,q <= 2e5
Mini examples for mental simulation:
1) Boundary example: Answer should be 0. Explain expected behavior and why naive logic may fail.
2) Adversarial example: Answer equals interval length. Explain expected behavior and why naive logic may fail.
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
- •n,q <= 2e5
Analysis
Key Insight
Sorting plus Fenwick operations. This step should reduce search space or formalize correctness. State why this insight changes your algorithm choice.
offlinefenwicksorting