zoj1314无源汇有上下界最大流

http://wenku.baidu.com/link?url=PS0EYD-M-bP9eYAPjRXxULXdR5romUR7WoON0wPkJ4ELrJs1uDcsFG2-7WwTgh48e8tMgqq1r_fUgCciFz5a3Rk_kHJ8Ni_d4YVGIv-eyAG

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <climits>
#include <string>
#include <iostream>
#include <map>
#include <cstdlib>
#include <list>
#include <set>
#include <queue>
#include <stack>
using namespace std;
int s;int e;
const int INF=0xfffffff;
int Min(int a,int b)
{
    return a>b?b:a;
}
const int maxn=444;
int du[maxn];
int Map[maxn][maxn];
int Map1[maxn][maxn];
int level[maxn];
bool bfs()
{
    queue<int > q;q.push(s);
    memset(level,0,sizeof(level));level[s]=1;
    while(!q.empty()){
        int cur=q.front(); q.pop();
        for(int i=s;i<=e;i++){
            if(Map[cur][i]&&!level[i]){
                level[i]=level[cur]+1;
                q.push(i);
            }
        }
    }
    return level[e];
}

int dfs(int x,int val)
{
    int sum=0;
    if(x==e) return val;
    for(int i=s;val&&i<=e;i++){
        if(Map[x][i]&&level[i]==level[x]+1){
            int t=dfs(i,Min(val,Map[x][i]));
            Map[x][i]-=t;Map[i][x]+=t;
            val-=t;sum+=t;
        }
    }
    if(sum==0) level[x]=-1;
    return sum;
}

int dinic()
{
    for(int i=0;i<=e;i++)
        for(int j=0;j<=e;j++)
        Map[i][j]=Map1[i][j];
    int ans=0;int t;
    while(bfs()){
        while(t=dfs(s,INF)) ans+=t;
    }
    return ans;
}
int l[1111111];
int a[1111111];int b[1111111];
int main()
{
    int Icase;int n;int m;
    int c;int d;
    scanf("%d",&Icase);
    while(Icase--){
        scanf("%d%d",&n,&m);
        s=0;e=n+1;
        for(int i=0;i<=e;i++)
            du[i]=0;
        for(int i=0;i<=e;i++)
            for(int j=0;j<=e;j++)
            Map1[i][j]=0;
        int sum=0;

        for(int i=0;i<m;i++){
            scanf("%d%d",&a[i],&b[i]);scanf("%d",&c);scanf("%d",&d);
            du[a[i]]-=c;du[b[i]]+=c;
            Map1[a[i]][b[i]]=d-c;
            l[i]=c;
        }


        for(int i=1;i<=n;i++){
            if(du[i]<0) Map1[i][e]=-du[i];
            if(du[i]>0) Map1[s][i]=du[i];
        }
        int ans=dinic();
       // cout<<ans<<endl;system("pause");
        int flag=0;
        for(int i=0;i<=e;i++)
        if(Map[s][i]){flag=1;break;}
        if(!flag){
            printf("YES
");
            for(int i=0;i<m;i++){
                cout<<Map1[a[i]][b[i]]-Map[a[i]][b[i]]+l[i]<<endl;
            }
        }
        else cout<<"NO"<<endl;
    }
    return 0;
}

du[i]=所有入边下界和-所有出边下界和  设源点s，汇点e

如果du[i]<0 , i->e=-du[i]  流出的流量减少的多 就补全一条边

如果du[i]>0, s->=du[i]     流入的流量减少的多 也补全一条边