Are these the shortest times?

Someone has worked out the shortest travel time from station s to every station, and handed you the list d. Check it without trusting it. Return True if every entry is right: d[v] is the least number of minutes from s to v, or None exactly when v cannot be reached. Otherwise return False.

edges = [(0, 1, 4), (0, 2, 1), (2, 1, 2),
         (1, 3, 1), (2, 3, 5), (3, 4, 3)]
are_shortest(5, edges, 0, [0, 3, 1, 4, 7])   # True
are_shortest(5, edges, 0, [0, 4, 1, 5, 8])   # False

In the second call, the line 2 → 1 reaches 1 in 1 + 2 = 3 minutes, less than the claimed 4. Lines are one-way, and times are whole numbers from 0 up. A line can take 0 minutes.

Limits

• Up to 100,000 stations and about 150,000 lines.
• Aim for O(V + E): read each line a fixed number of times. The big tests have 3 seconds each. Running a shortest-path search yourself and comparing is accepted too.