Leetcode 1334. Find the City With the Smallest Number of Neighbors at a Threshold Distance

Given a weighted undirected graph of n cities, compute for each city how many other cities are reachable within a given distanceThreshold via shortest paths, and return the city with the smallest such count (breaking ties by largest index). This is essentially an all-pairs shortest-path/counting problem on a small graph (n ≤ 100).