poj1459 最大流Dinic

比较简单。

#include<stdio.h>
#include<string.h>
#include<queue>
#define maxn 110
#define INF 99999999
using namespace std;
int vis[maxn],n,map[maxn][maxn];
int min(int x,int y)
{return x<y?x:y;}
int dfs(int u,int low)
{
    int i,a;
    if(u==n+1)
        return low;
    for(i=0;i<=n+1;i++)
    {
        if(vis[i]==vis[u]+1&&map[u][i]>0)
        {
            a=dfs(i,min(low,map[u][i]));
            if(!a)continue;
            map[u][i]-=a;
            map[i][u]+=a;
            return a;
        }
    }
    return 0;
}
bool BFS()
{
    int i;
    queue<int>q;
    memset(vis,-1,sizeof(vis));
    vis[0]=0;
    q.push(0);
    while(!q.empty())
    {
        int t=q.front();
        q.pop();
        for(i=0;i<=n+1;i++)
        {
            if(vis[i]<0&&map[t][i]>0)
            {
                vis[i]=vis[t]+1;
                q.push(i);
            }
        }
    }
    if(vis[n+1]>0)return true;
    return false;
}
int main()
{
    int i,nc,np,m;
    while(scanf("%d %d %d %d",&n,&np,&nc,&m)!=EOF)
    {
        memset(map,0,sizeof(map));
        for(i=0;i<m;i++)
        {
            int x,y,z;
            while(getchar()!='(');
            scanf("%d,%d)%d",&x,&y,&z);
            map[x+1][y+1]+=z;
        }
        for(i=0;i<np;i++)
        {
            int x,y;
            while(getchar()!='(');
            scanf("%d)%d",&x,&y);
            map[0][x+1]=y;
        }
        for(i=0;i<nc;i++)
        {
            int x,y;
            while(getchar()!='(');
            scanf("%d)%d",&x,&y);
            map[x+1][n+1]=y;
        }
        int ans=0;
        while(BFS())
        {
            while(1)
            {
                int a=dfs(0,INF);
                if(!a)break;
                ans+=a;
            }
        }
        printf("%d
",ans);
    }
}