Simple (?) Min-Cost Max-Flow
◮ Forget about the costs and just find a max-flow
◮ Repeat:
– Take the residual graph
– Find a negative-cost cycle using Bellman-Ford
◮ If there is none, finish
– Circulate flow through the cycle to decrease the total cost,
until one of the edges is saturated
◮ The total amount of flow doesn’t change!
◮ Time complexity: very slow