bool型floyd算法

#include<bits/stdc++.h>
using namespace std;

const int N = 110;
bool g[N][N];
int n,m;

void floyd()
{
    for(int k = 1;k<=n;k++)
        for(int i = 1;i<=n;i++)
            for(int j = 1;j<=n;j++)
                g[i][j] = g[i][j] || (g[i][k] && g[k][j]);
}

int main()
{
    cin>>n>>m;
    while(m--)
    {
        int a,b;
        cin>>a>>b;
        g[a][b] = true;
    }
    for(int i = 1;i<=n;i++)g[i][i] = true;
    floyd();


    int ans = 0;
    for(int i = 1;i<=n;i++)
    {
        bool flag = true;
        for(int j = 1;j<=n;j++)
        {
            flag = flag && (g[i][j] || g[j][i]);
        }
        if(flag)ans++;
    }
    cout<<ans<<endl;
    return 0;
}