poj3615

floyd变形

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#include <iostream>

#include <cstdio>

#include <cstdlib>

#include <cstring>

using namespace std;



#define maxn 306

#define inf 0x3f3f3f3f



int n, m, t;

int map[maxn][maxn];



void input()

{

    scanf("%d%d%d", &n, &m, &t);

    for (int i = 0; i < n; i++)

        for (int j = 0; j < n; j++)

            map[i][j] = inf;

    for (int i = 0; i < m; i++)

    {

        int a, b, w;

        scanf("%d%d%d", &a, &b, &w);

        a--;

        b--;

        map[a][b] = w;

    }

}



void make()

{

    for (int k = 0; k < n; k++)

        for (int i = 0; i < n; i++)

            for (int j = 0; j < n; j++)

                map[i][j] = min(map[i][j], max(map[i][k], map[k][j]));

}



void work()

{

    for (int i = 0; i < t; i++)

    {

        int a, b;

        scanf("%d%d", &a, &b);

        a--;

        b--;

        if (map[a][b] == inf)

            printf("-1\n");

        else

            printf("%d\n", map[a][b]);

    }

}



int main()

{

    //freopen("t.txt", "r", stdin);

    input();

    make();

    work();

    return 0;

}