About this puzzle

The Relay — practice the decision, scored against the optimum

What does the The Relay puzzle teach?

Connect every node at the lowest total link cost — that's a minimum spanning tree. Kruskal: add the cheapest edge that joins two separate components, skipping any that would form a cycle.

Why do interviews ask about this?

Minimum spanning tree is the canonical connect-everything-at-least-cost question — Kruskal/Prim with union-find probes greedy-correctness reasoning and disjoint-set structures.

How is it scored?

The engine computes the provably-optimal answer for the exact instance you played (dynamic programming, shortest-path, or exhaustive search — never a heuristic) and scores your attempt as a percentage of it. No login needed to see your score.