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: Lock Frontiers.
Without visited state, the party loops forever or revisits expensive terrain.
How you win
- 1Recognize when Implicit graph breadth-first search matches the clues
- 2Keep this true after every move: the queue contains exactly the unseen, legal lock states discovered at nondecreasing turn counts
- 3Reach the result within O(10^4) time and space
Rules and pressure
- Target cost: O(10^4) time and space
- State rule: the queue contains exactly the unseen, legal lock states discovered at nondecreasing turn counts
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
Every combination is a graph node; turning one wheel by one notch creates eight implicit neighbors.
Your call · What does the first wheel become when 0000 turns one notch downward?