Section 7.7 Extensions to the Maximum Flow Problem

This problem changes what we have been talking about by adding multiple sources and sinks. Instead of maximizing the flow value, we will have sources with fixed supply values and sources with fixed demand values. Here we want to satisfy all demand with all our supply instead of maximizing some value. The demand of a node can be greater than, equal to, or less than zero. If demand is greater than supply, the node is a sink; if demand is zero, the node is an interior node and if the node wishes to send out more than it receives (negative demand) then it is a source.