floyed

floyed

#include <bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
const int N=500;
int s[N][N];
int main()
{
    int n,m,t;
//  cout<<INF<<endl;
    cin>>n>>m>>t;
    for(int i=1;i<=n;i++)
    {
        for(int j=1;j<=n;j++){
            if(i==j)s[i][j]=0;
            else s[i][j]=INF;
        }
    }
    while(m--)
    {
        int a,b,c;
        cin>>a>>b>>c;
        s[a][b]=min(c,s[a][b]);
    }
    for(int k=1;k<=n;k++)
    {
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=n;j++)
            {
                s[i][j]=min(s[i][j],s[i][k]+s[k][j]);
            }
        }
    }
    while(t--)
    {
        int a,b;
        cin>>a>>b;
        if(s[a][b]<INF/2)cout<<s[a][b];
        else cout<<"impossible";
        cout<<endl;
    }
    return 0;
}