hdu 3667 (费用流，拆边)

#include<stdio.h>
#include<queue>
#include<string.h>
const int N=110;
const int inf=0x3fffffff;
using namespace std;
int pp[6]={0,1,3,5,7,9};
int dist
,head
,num,n,start,end,vis
,pre
,k;
struct edge
{
int st,ed,cost,flow,next;
}e[N*1000];
void addedge(int x,int y,int c,int w)
{
e[num].st=x;e[num].ed=y;e[num].cost=c; e[num].flow=w;e[num].next=head[x];head[x]=num++;
e[num].st=y;e[num].ed=x;e[num].cost=-c;e[num].flow=0;e[num].next=head[y];head[y]=num++;
}
int SPFA()
{
int i,v,u;
queue<int>Q;
for(i=start;i<=end;i++)
{dist[i]=inf;vis[i]=0;pre[i]=-1;}
dist[start]=0;vis[start]=1;
Q.push(start);
while(!Q.empty())
{
u=Q.front();Q.pop();
vis[u]=0;
for(i=head[u];i!=-1;i=e[i].next)
{
v=e[i].ed;
if(e[i].flow>0&&dist[v]>dist[u]+e[i].cost)
{
pre[v]=i;dist[v]=dist[u]+e[i].cost;
if(vis[v]==0)
{
vis[v]=1;
Q.push(v);
}
}
}
}
if(pre[end]==-1)
return 0;
return 1;
}
int Mincost()
{
int minflow,maxflow=0,mincost=0,i;
while(SPFA())
{
minflow=inf;
for(i=pre[end];i!=-1;i=pre[e[i].st])
if(minflow>e[i].flow)
minflow=e[i].flow;
maxflow+=minflow;
for(i=pre[end];i!=-1;i=pre[e[i].st])
{
e[i].flow-=minflow;
e[i^1].flow+=minflow;
mincost+=e[i].cost*minflow*minflow;
}
}
if(maxflow==k)
return mincost;
else return -1;

}
int main()
{
int i,j,x,y,c,w,m;
while(scanf("%d%d%d",&n,&m,&k)!=-1)
{
memset(head,-1,sizeof(head));
num=0;start=0;end=n+1;
for(i=0;i<m;i++)
{
scanf("%d%d%d%d",&x,&y,&c,&w);
for(j=1;j<=w;j++)
addedge(x,y,pp[j]*c,1);
}
addedge(start,1,0,k);
addedge(n,end,0,k);
printf("%d\n",Mincost());
}
return 0;
}