[Swust OJ 412]--医院设置(floyd算法)

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <cstring>
 4 using namespace std;
 5 #define inf 0x3f3f3f
 6 
 7 int n, ptr[101], mpt[101][101], L, R;
 8 void Floyd(){
 9     for (int k = 1; k <= n; k++){
10         for (int i = 1; i <= n; i++){
11             for (int j = 1; j <= n; j++)
12                 mpt[i][j] = min(mpt[i][j], mpt[i][k] + mpt[k][j]);
13         }
14     }
15 }
16 int main(){
17     int i, j, sum, tmp;
18     while (cin >> n){
19         sum = inf;
20         memset(mpt, inf, sizeof(mpt));
21         for (i = 1; i <= n; i++){
22             cin >> ptr[i] >> L >> R;
23             mpt[L][i] = mpt[i][L] = mpt[R][i] = mpt[i][R] = 1;
24         }
25         Floyd();
26         for (i = 1; i <= n; i++){
27             tmp = 0;
28             for (j = 1; j <= n; j++) {
29                 if (i != j)
30                     tmp += mpt[i][j] * ptr[j];
31             }
32             sum = min(sum, tmp);
33         }
34         cout << sum << endl;
35     }
36     return 0;
37 }