Roy-Warshall

#include <iostream>
using namespace std;

int n,m,i,j,k,a[101][101];
int main()
{
    cin>>n>>m;
    for(k=1;k<=m;++k)
    {
        cin>>i>>j;
        a[i][j]=1;
    }
    for(k=1;k<=n;++k)
        for(i=1;i<=n;++i)
            for(j=1;j<=n;++j)
                if(a[i][j]==0) a[i][j]=a[i][k]*a[k][j];
    for(i=1;i<=n;++i)
    {
        for(j=1;j<=n;++j)
            cout<<a[i][j]<<' ';
        cout<<'\n';
    }
    return 0;

}