【HDU1875】畅通工程再续（MST基础题）

更改成实形数即可。第一次敲完直接交，CE了一次。晕。

 #include <iostream>
 #include <cstring>
 #include <cstdio>
 #include <cstdio>
 #include <cctype>
 #include <cmath>
 #include <algorithm>
 #include <numeric>

 #define typec double
 using namespace std;

 const typec inf = 0xffff;
 const int V = ;
 int vis[V];
 typec lowc[V], Map[V][V], point[V][];

 typec prim (typec cost[][V], int n) {
     int i, j, p;
     typec minc, res = ;
     memset(vis, , sizeof(vis));
     vis[] = ;
     for (i = ; i < n; ++ i) lowc[i] = cost[][i];
     for (i = ; i < n; ++ i) {
         minc = inf; p = -;
         for (j = ; j < n; ++ j ) {
             if ( == vis[j] && minc > lowc[j]) {
                 minc = lowc[j];
                 p = j;
             }
         }
         if (inf == minc) return -;
         res += minc;
         vis[p] = ;
         for (j = ; j < n; ++ j) {
             if ( == vis[j] && lowc[j] > cost[p][j]) {
                 lowc[j] = cost[p][j];
             }
         }
     }
     return res;
 }

 double cal_dis (double x1, double y1, double x2, double y2) {
     return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
 }

 int main () {
     int T; scanf("%d", &T);
     while (T --) {
         //vector<pair<double, double> > p;
         int n; scanf("%d", &n);
         for (int i = ; i < n; ++ i) {
             scanf("%lf%lf", &point[i][], &point[i][]);
         }

         for (int i =  ; i < ; ++ i) {
             for (int j = ; j < ; ++ j) {
                 if (i == j) Map[i][j] = ;
                 else Map[i][j] = inf;
             }
         }

         for (int i = ; i < n; ++i) {
             for (int j = i + ; j < n; ++ j) {
                 double w = cal_dis(point[i][], point[i][],point[j][],point[j][]);
                 if (w >=  && w <= )
                     Map[i][j] = Map[j][i] = min(Map[i][j], w);
                 else continue;
                 /*cout << Map[i][j] << endl;
                 cout << Map[j][i] << endl;*/
             }
         }

         /*for (int i = 0; i < 2; ++ i) {
             for (int j = 0 ; j < 2; ++ j) {
                 cout << Map[i][j] << " ";
             }
             cout << endl;
         }*/
         double ans =  * prim(Map, n);
         if (ans > )
             printf("%.1lf\n", ans);
         else {
             printf("oh!\n");
         }
         //cout << prim (Map, n) << endl;
     }
     return ;
 }