4. Consider the graph below. You start at point A and wish to reach point B, only going downward at each step. When traveling an edge, you must pay the toll value associated with it. You wish to compute a path from A to B whose total cost is as small as possible. 2 3/2 The general problem is as follows: you are given a directed acyclic graph (DAG) with n vertices (named 1,2,.. . , n), and a list of m edges (u, v) where u 1 has at least an edge from a smaller node u