Time:Time: Space:Space: C++ class Solution: def numberOfPaths(self, n: int, corridors: List[List[int]]) -> int: ans = 0 graph = [[False] * 1001 for _ in range(n + 1)] for u, v in corridors: graph[u][v] = True graph[v][u] = True for u, v in corridors: for i in range(1, n + 1): if graph[u][i] and graph[i][v]: ans += 1 return ans // 3