Problem context and objectives
Mission briefing
Game event engineer · Actions arrive faster than the world can resolve them
Process events in the exact order promised by the data structure: The Next Higher Signal.
The wrong removal order changes gameplay and creates impossible replays.
How you win
- 1Recognize when Decreasing unresolved stack matches the clues
- 2Keep this true after every move: stack values are non-increasing, including equal values, and every stack index still lacks a known next greater value
- 3Reach the result within O(n)
Rules and pressure
- Target cost: O(n)
- State rule: stack values are non-increasing, including equal values, and every stack index still lacks a known next greater value
Lesson 1 of 3
The stack stores indices whose next greater value is still unknown. A stronger arrival resolves smaller tops one at a time.
Your call · Value 4 arrives while stack values are [2,2]. What happens?