[ACM模板]ZKW MCMF费用流

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    #include <cstdio>    #include <cstring>    #include<vector>    #include <iostream>    using namespace std;    const int maxint=~0U>>1;    /*      用法:n节点个数。求解节点1到节点n的费用流      (1)设置n      (2)addEdge(from,to,cap,cost)      (3)solve()    */    #define N 1000    #define M 50000    int n,m,pi1,cost=0;    bool v[N];    struct etype    {        int t,c,u;        etype *next,*pair;        etype(){}        etype(int t_,int c_,int u_,etype* next_):            t(t_),c(c_),u(u_),next(next_){}        //void* operator new(unsigned,void* p){return p;}    } *e[M];    etype *Pe=new etype[M];    int aug(int no,int m)    {        if(no==n)return cost+=pi1*m,m;        v[no]=true;        int l=m;        for(etype *i=e[no];i;i=i->next)            if(i->u && !i->c && !v[i->t])            {                int d=aug(i->t,l<i->u?l:i->u);                i->u-=d,i->pair->u+=d,l-=d;                if(!l)return m;            }        return m-l;    }    bool modlabel()    {        int d=maxint;        for(int i=1;i<=n;++i)if(v[i])            for(etype *j=e[i];j;j=j->next)                if(j->u && !v[j->t] && j->c<d)d=j->c;        if(d==maxint)return false;        for(int i=1;i<=n;++i)if(v[i])            for(etype *j=e[i];j;j=j->next)                j->c-=d,j->pair->c+=d;        pi1 += d;        return true;    }    int solve(){        cost=0;        do do memset(v,0,sizeof(v));        while(aug(1,maxint));        while(modlabel());        return cost;    }    void addEdge(int s,int t,int u,int c){        e[s]=new(Pe++)etype(t, c,u,e[s]);        e[t]=new(Pe++)etype(s,-c,0,e[t]);        e[s]->pair=e[t];        e[t]->pair=e[s];    }///////////////////////以上为zkw模板////////////////////////////int main()    {        scanf("%d%d",&n,&m);        for (int i=1;i<=m;i++){          int a,b,c,d;scanf("%d%d%d%d",&a,&b,&c,&d);          addEdge(a,b,c,d);        }        printf("%d\n",solve());        return 0;    }
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