I'm stuck on solving this problem, and I literally have no ideas left. The only idea I had was to find the center of the graph (the vertex with the minimum eccentricity), but I've been trying to optimize the solution for a long time now, and nothing is working—there's nothing I can do about the fact that Floyd-Warshall runs in (O(N^3)). I need a nudge in the right direction toward the correct solution.