Contest Guide

Standard contest duration is 2 hours unless a contest page explicitly says otherwise.

Read this once before your first submission to avoid preventable verdicts and penalty. Contest pages will show overrides if timing/rules differ.

Difficulty Tiers

Tier 1

Entry level. Direct implementation and basic simulation.

Tier 2

Standard contest difficulty. Efficient data structures and clean logic.

Tier 3

Advanced. Multi-step reasoning, strict edge cases, easy WA pitfalls.

Tier 4

Hardest. Tight proofs, heavy optimization, and uncommon techniques.

Each problem has a number slot like 1, 2, 3, 3b1, 3b2, 4, 5.
Bonus slots (for example 3b1, 3b2) are harder variants with separate points.
Difficulty tiers are shown as levels 1 / 2 / 3 / 4: 1 easiest, 4 hardest.
If a problem has partial scoring, standings may show earned points below full score.
Bonus versions are intended as larger constraints or tighter data ranges. If your main solution is truly optimal, it should pass bonus without algorithm changes.

Submissions enter a queue and are judged in order. Queue size may be limited by server capacity.
Language runtime is calibrated so pypy3/cpp/java are judged under the same fairness model.
Wrong submissions normally add penalty before first accepted result on that problem.
For heuristic problems, your best score is kept; lower later scores do not replace your maximum.
Standings rank by total points first, then penalty/time tie-breaks.