【HDU1102】Constructing Roads（MST基础题）

最小生成树水题。prim一次AC

 

 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 int V = 105;

14 const int inf = 0xffff;

15 int vis[V]; typec lowc[V];

16 int Map[105][105];

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]; p = j;

29             }

30         }

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

32         res += minc; vis[p] = 1;

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

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

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

36             }

37         }

38     }

39     return res;

40 }

41 

42 int main () {

43     //cout << inf <<endl;

44     int n;

45     while (cin >> n) {

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

47             for (int j = 0 ; j < n; ++ j) {

48                 scanf("%d", &Map[i][j]);

49             }

50         }

51         int ok_line; cin >> ok_line;

52         for (int i = 0; i < ok_line; ++ i) {

53             int s, e;

54             scanf("%d%d", &s, &e);

55             Map[s - 1][e - 1] = Map[e - 1][s - 1] = 0;

56         }

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

58     }

59     return 0;

60 }