Next place to visit by distance

Problem You are given places, each with a distance from the current location. Support repeated lookups of "which place should be visited next" — each query returns the nearest place not yet visited and marks it visited.

Input / Output

• Input: list of (place, distance) pairs, then a sequence of next() queries.
• Output: for each query, the nearest unvisited place.

Constraints

• Up to 10^5 places and queries — per-query linear scans (O(n) each) are the naive baseline to beat.

Example

• places = [(A,5),(B,2),(C,9)] → next() = B, next() = A, next() = C.