最短路之Floyd

#include<bits/stdc++.h>
using namespace std;
const int maxn = 300+10;
int n,m,f[maxn][maxn],t;

int main(){
    memset(f,127/3,sizeof(f));
    scanf("%d%d%d",&n,&m,&t);
    for(int i = 1;i <= m;++i){
        int x,y,z;
        scanf("%d%d%d",&x,&y,&z);
        f[x][y] = z;
    }
    for(int k = 1;k <= n;++k)
        for(int i = 1;i <= n;++i)
            for(int j = 1;j <= n;++j){
                if(i != j && j != k)f[i][j] = min(f[i][j],f[i][k] + f[k][j]);
            }
    for(int i = 1;i <= t;++i){
        int a,b;
        scanf("%d%d",&a,&b);
        if(f[a][b] == 707406378)printf("-1\n");
        else printf("%d\n",f[a][b]);
    }
    return 0;
}