Problem context and objectives
Mission briefing
Expedition navigator · Safe camps and hazards form a connected world map
Find a valid route while marking every place already explored: Parallel Terms.
Without visited state, the party loops forever or revisits expensive terrain.
How you win
- 1Recognize when Layered topological schedule matches the clues
- 2Keep this true after every move: the current queue layer contains exactly the courses available in the same earliest semester
- 3Reach the result within O(V + E) time and space
Rules and pressure
- Target cost: O(V + E) time and space
- State rule: the current queue layer contains exactly the courses available in the same earliest semester
New words in this mission
Open a term for a plain-language explanation.durable queue+
A waiting line that keeps work until a consumer finishes it. It absorbs bursts and lets failed work be retried.
Lesson 1 of 3
Freeze the ready cohort at the start of each semester; courses unlocked during launch wait for the next semester.
Your call · Courses 1 and 2 unlock course 3 during semester 1. When may course 3 launch?