Suppose that the costs of 0-2 and 1-3 in Figure 22.40 are -1, instead of 1. Show how to find a mincost maxflow by transforming the network to a network with positive costs and finding a mincost maxflow of the new network.
Figure 22.40. Maxflows in flow networks with costs
These flows all have the same (maximal) value, but their costs (the sum of the products of edge flows and edge costs) differ. The maxflow in the center has minimal cost (no maxflow has lower cost).
