poj 3615 Cow Hurdles

赤裸裸的floyd，思路很直接。很容易想到。

/*
POJ: 3615 Cow Hurdles
*/
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>

#define MaxN 305
#define MaxD (1 << 20)

using namespace std;

long map[MaxN][MaxN];
int n, m, t;

void solve()
{
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++)
for(int k = 1; k <= n; k++)
map[j][k] = min(map[j][k], max(map[j][i], map[i][k]));
}

int main()
{
//freopen("data.in", "rb", stdin);
while(scanf("%d%d%d", &n, &m, &t) != EOF) {
for(int i = 0; i <= n; i++) {
for(int j = 0; j <= n; j++) {
map[i][j] = MaxD;
}
}

for(int i = 0; i < m; i++) {
int a, b;
long c;
scanf("%d%d%ld", &a, &b, &c);
map[a][b] = c;
}

solve();

for(int i = 0; i < t; i++) {
int a, b;
scanf("%d%d", &a, &b);
if(map[a][b] < MaxD)
printf("%d\n", map[a][b]);
else
printf("-1\n");
}
}

return 0;
}