BZOJ1834 [ZJOI2010]network 网络扩容（最小费用最大流）

挺直白的构图。。最小费用最大流的定义。

#include<cstdio>
#include<cstring>
#include<queue>
#include<algorithm>
using namespace std;
#define INF (1<<30)
#define MAXN 11111
#define MAXM 2222222
struct Edge{
    int u,v,cap,cost,next;
}edge[MAXM];
int head[MAXN];
int NV,NE,vs,vt;

void addEdge(int u,int v,int cap,int cost){
    edge[NE].u=u; edge[NE].v=v; edge[NE].cap=cap; edge[NE].cost=cost;
    edge[NE].next=head[u]; head[u]=NE++;
    edge[NE].u=v; edge[NE].v=u; edge[NE].cap=0; edge[NE].cost=-cost;
    edge[NE].next=head[v]; head[v]=NE++;
}
bool vis[MAXN];
int d[MAXN],pre[MAXN];
bool SPFA(){
    for(int i=0;i<NV;++i){
        vis[i]=0;
        d[i]=INF;
    }
    vis[vs]=1;
    d[vs]=0;
    queue<int> que;
    que.push(vs);
    while(!que.empty()){
        int u=que.front(); que.pop();
        for(int i=head[u]; i!=-1; i=edge[i].next){
            int v=edge[i].v;
            if(edge[i].cap && d[v]>d[u]+edge[i].cost){
                d[v]=d[u]+edge[i].cost;
                pre[v]=i;
                if(!vis[v]){
                    vis[v]=1;
                    que.push(v);
                }
            }
        }
        vis[u]=0;
    }
    return d[vt]!=INF;
}
int MCMF(){
    int res=0;
    while(SPFA()){
        int flow=INF,cost=0;
        for(int u=vt; u!=vs; u=edge[pre[u]].u){
            flow=min(flow,edge[pre[u]].cap);
        }
        for(int u=vt; u!=vs; u=edge[pre[u]].u){
            edge[pre[u]].cap-=flow;
            edge[pre[u]^1].cap+=flow;
            cost+=flow*edge[pre[u]].cost;
        }
        res+=cost;
    }
    return res;
}
int MF(){
    int res=0;
    while(SPFA()){
        int flow=INF,cost=0;
        for(int u=vt; u!=vs; u=edge[pre[u]].u){
            flow=min(flow,edge[pre[u]].cap);
        }
        res+=flow;
        for(int u=vt; u!=vs; u=edge[pre[u]].u){
            edge[pre[u]].cap-=flow;
            edge[pre[u]^1].cap+=flow;
        }
    }
    return res;
}
int u[MAXN],v[MAXN],c[MAXN],w[MAXN];
int main(){
    int n,m,k;
    scanf("%d%d%d",&n,&m,&k);
    vs=1; vt=n; NV=vt+1; NE=0;
    memset(head,-1,sizeof(head));
    for(int i=0; i<m; ++i){
        scanf("%d%d%d%d",u+i,v+i,c+i,w+i);
        addEdge(u[i],v[i],c[i],1);
    }
    int mxflow=MF();
    printf("%d ",mxflow);
    vs=1; vt=0; NV=n+1; NE=0;
    memset(head,-1,sizeof(head));
    addEdge(n,vt,mxflow+k,0);
    for(int i=0; i<m; ++i){
        addEdge(u[i],v[i],c[i],0);
        addEdge(u[i],v[i],INF,w[i]);
    }
    printf("%d",MCMF());
    return 0;
}