Network Delay Time

You are given a number of nodes n and a list of directed edges in the format (u, v, w) where u can reach v with the delay time w. Determine the minimum time it takes to reach all nodes from a starting node k. If any node is unreachable, return -1. Input format: The first line contains three integers n, m (1 <= n <= 100, 1 <= m <= 1000) and k, representing the number of nodes, number of edges, and the starting node respectively. The next m lines contain three integers u, v, w. Output format: An integer representing the minimum time to reach all nodes or -1 if it is not possible. Example: Input: 4 4 2 1 2 1 1 3 3 2 3 1 3 4 1 Output: 4