Floyd求最小环

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#define rep(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
int n,map[1005][1005],dist[1005][1005],Min;
void have_done()
{
    rep(k,1,n)
    {
        rep(i,1,k-1)
        {
            rep(j,1,k-1)
            {
                if(map[i][k]+map[k][j]+dist[i][j]<Min)
                {
                    Min=map[i][k]+map[k][j]+dist[i][j];
                }
                dist[i][j]=min(dist[i][j],map[i][k]+map[k][j]);
            }

        }
    }
}
int main()
{
    Min=100000;
    scanf("%d",&n);
    rep(i,1,n)
        rep(j,1,n)
        {
            scanf("%d",&map[i][j]);
        }
    have_done();
    cout<<Min<<endl;
}