【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。

 

 1 #include <iostream>

 2 #include <cstring>

 3 #include <cstdio>

 4 #include <cstdio>

 5 #include <cctype>

 6 #include <cmath>

 7 #include <algorithm>

 8 #include <numeric>

 9 

10 #define typec double

11 using namespace std;

12 

13 const typec inf = 0xffff;

14 const int V = 1005;

15 int vis[V];

16 typec lowc[V], Map[V][V], point[V][2];

17 

18 typec prim (typec cost[][V], int n) {

19     int i, j, p;

20     typec minc, res = 0;

21     memset(vis, 0, sizeof(vis));

22     vis[0] = 1;

23     for (i = 1; i < n; ++ i) lowc[i] = cost[0][i];

24     for (i = 1; i < n; ++ i) {

25         minc = inf; p = -1;

26         for (j = 0; j < n; ++ j ) {

27             if (0 == vis[j] && minc > lowc[j]) {

28                 minc = lowc[j];

29                 p = j;

30             }

31         }

32         if (inf == minc) return -1;

33         res += minc;

34         vis[p] = 1;

35         for (j = 0; j < n; ++ j) {

36             if (0 == vis[j] && lowc[j] > cost[p][j]) {

37                 lowc[j] = cost[p][j];

38             }

39         }

40     }

41     return res;

42 }

43 

44 double cal_dis (double x1, double y1, double x2, double y2) {

45     return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));

46 }

47 

48 int main () {

49     int T; scanf("%d", &T);

50     while (T --) {

51         //vector<pair<double, double> > p;

52         int n; scanf("%d", &n);

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

54             scanf("%lf%lf", &point[i][0], &point[i][1]);

55         }

56 

57         for (int i = 0 ; i < 105; ++ i) {

58             for (int j = 0; j < 105; ++ j) {

59                 if (i == j) Map[i][j] = 0;

60                 else Map[i][j] = inf;

61             }

62         }

63 

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

65             for (int j = i + 1; j < n; ++ j) {

66                 double w = cal_dis(point[i][0], point[i][1],point[j][0],point[j][1]);

67                 if (w >= 10 && w <= 1000)

68                     Map[i][j] = Map[j][i] = min(Map[i][j], w);

69                 else continue;

70                 /*cout << Map[i][j] << endl;

71                 cout << Map[j][i] << endl;*/

72             }

73         }

74 

75         /*for (int i = 0; i < 2; ++ i) {

76             for (int j = 0 ; j < 2; ++ j) {

77                 cout << Map[i][j] << " ";

78             }

79             cout << endl;

80         }*/

81         double ans = 100 * prim(Map, n);

82         if (ans > 0)

83             printf("%.1lf\n", ans);

84         else {

85             printf("oh!\n");

86         }

87         //cout << prim (Map, n) << endl;

88     }

89     return 0;

90 }