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OI-codes/AcWing/854/854.cpp

35 lines
792 B
C++

#include <bits/stdc++.h>
using namespace std;
int n, m, k, x, y, z, f[205][205];
int main() {
cin >> n >> m >> k;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= n; j++) {
f[i][j] = i == j ? 0 : 0x3f3f3f3f3f;
}
}
for (int i = 1; i <= m; i++) {
cin >> x >> y >> z;
f[x][y] = min(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++) {
f[i][j] = min(f[i][j], f[i][k] + f[k][j]);
}
}
}
for (int i = 1; i <= k; i++) {
cin >> x >> y;
if (f[x][y] > 0x1fffffff) {
cout << "impossible" << endl;
} else {
cout << f[x][y] << endl;
}
}
return 0;
}