You are given a road network as a weighted directed graph where edge weights represent toll costs. Find the minimum cost path between a source city and a destination city.
[u, v, toll], a source and a destination.cities = 5
roads = [[0,1,4],[0,2,2],[1,3,3],[2,1,1],[2,3,5],[3,4,2]]
source = 0, destination = 4
Output: 8 -- path: 0->2->1->3->4