bzoj 1143: [CTSC2008]祭祀river

这是最大独立集？？最小点覆盖？？（反正就是总数减去匈牙利算出来的就是）

这个题加一个Floyd建边就行

#include<bits/stdc++.h>
#define N 200005
#define LL long long
#define inf 0x3f3f3f3f
#define ls tr[x][0]
#define rs tr[x][1]
using namespace std;
inline int ra()
{
    int x=0,f=1; char ch=getchar();
    while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}
    while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}
    return x*f;
}
bool mp[505][505];
int T,y[505],lk[505],n,m,ans;
int dfs(int x)
{
    for (int i=1; i<=n; i++)
        if (mp[x][i] && y[i]!=T)
        {
            y[i]=T;
            if (lk[i]==0 || dfs(lk[i]))
            {
                lk[i]=x;
                return 1;
            }
        }
    return 0; 
}
int main()
{
    n=ra(); m=ra();
    for (int i=1; i<=m; i++)
        mp[ra()][ra()]=1;
    for (int k=1; k<=n; k++)    
        for (int i=1; i<=n; i++)
            for (int j=1; j<=n; j++)
                if (mp[i][k] && mp[k][j]) mp[i][j]=1;
    for (int i=1; i<=n; i++)
    {
        T++; ans+=dfs(i);
    }
    cout<<n-ans;
}