poj1698

题解：

网络流

然后似乎反着做块？

代码：

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
const int N=405;
int T,qq[8],vvis,q[N*10],n,m,t,l,sum,dis[N],x,y,ans,f[N],z,a[N][N];
int bfs()
{
    memset(dis,0xff,sizeof dis);
    dis[n]=0;
    int l=0,r=1;
    q[1]=n;
    while (l<r)
     {
         int j=q[++l];
         for (int i=1;i<=n;i++)
          if (dis[i]<0&&a[i][j]>0)
           {
               dis[i]=dis[j]+1;
               q[++r]=i;
           }
         if (j==1)return 1;  
     }
    return 0; 
}
int dfs(int x,int y)
{  
    if (x==n)return y;        
    int tmp=y,t;  
    for (int i=1;i<=n&&tmp;i++)
     if (dis[i]+1==dis[x]&&a[x][i])
      {  
        t=dfs(i,min(a[x][i],tmp));  
        a[x][i]-=t;  
        a[i][x]+=t;  
        tmp-=t;  
      }  
    return y-tmp;  
}
int main()
{
    scanf("%d",&T);
    while (T--)
     {
         vvis=0;
         scanf("%d",&n);
         memset(a,0,sizeof a);
        for (int k=1;k<=n;k++)
          {
             for (int i=0;i<7;i++)scanf("%d",&qq[i]);
             scanf("%d%d",&t,&l);
             vvis+=t;
            for (int j=0;j<7;j++)
             if (qq[j])for (int i=0;i<l;i++)a[351+k][i*7+j+2]=1;
            a[1][k+351]=t;
         }
        for (int i=2;i<=351;i++)a[i][372]=1; 
        n=372; 
        ans=0;int t; 
        while (bfs())ans+=dfs(1,1e9);
        if (ans==vvis)puts("Yes");
        else puts("No"); 
     }
}