这个题目可以采用网络流的模型来解决。

在原图的基础上添加一个源点和汇点。对于每个Power Station，从源点引一条容量为pmax的弧；对于每个Consumer，引一条容量为cmax的弧到汇点；对于题目中给的三元组(u,v)z，从点u连一条容量为z的弧到点v。显然这样构图是满足题目要求的。然后求这个网络的最大流即可。

-The subject of network flow can be used to solve the model.



On the basis of the add a point of origin and one world. For each Power Station, from the point of origin lead a capacity for pmax arc　For each Consumer, lead a capacity for cmax arc to one world　For the questions in three yuan to group (u, v) z, from some u even have a capacity for z along the arc v. Apparently this composition is to meet the requirements of the subject. And then for the network s maximum flow can.