【HDU1879】继续畅通工程（MST基础题）

真心大水题。。。不多说。

 

 1 #include <iostream>

 2 #include <cstring>

 3 #include <cstdlib>

 4 #include <cstdio>

 5 #include <cctype>

 6 #include <cmath>

 7 #include <algorithm>

 8 #include <numeric>

 9 

10 #define typec int

11 using namespace std;

12 

13 const typec inf = 0xffff;

14 const int V = 105;

15 int vis[V];

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

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;

26         p = -1;

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

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

29                 minc = lowc[j];

30                 p = j;

31             }

32         }

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

34         res += minc;

35         vis[p] = 1;

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

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

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

39             }

40         }

41     }

42     return res;

43 }

44 

45 int main () {

46     int n;

47     while (~scanf("%d", &n)) {

48         if (!n) break;

49         for (int i = 0 ; i < V; ++i) {

50             for (int j = 0; j < V; ++ j) {

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

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

53             }

54         }

55 

56         for (int i = 0 ; i < n * (n - 1) / 2; ++i) {

57             int x, y, w, ok;

58             scanf("%d%d%d%d", &x, &y, &w, &ok);

59             if (!ok) {

60                 Map[x - 1][y - 1] = Map[y - 1][x - 1] = min(Map[x][y], w);

61             } else {

62                 Map[x - 1][y - 1] = Map[y - 1][x - 1] = 0;

63             }

64         }

65 

66         cout << prim(Map, n) << endl;

67     }

68     return 0;

69 }