5. Let G = (V,E) be a weighted directed graph. Design an algorithm to find a cycle in G of minimum weight. The algorithm should run in O(n) time. (20 points) 1 6. Let G = (V,E) be a weighted undirected graph, and let F be a subgraph of G that is a forest. Design an efficient algorithm to find a spanning tree in G that contains all the edges of F, and that has the minimum cost among all spanning trees containing F. (20 points)