计算最小生成树代价和

 1 /**
 2     普里姆算法构造最小生成树
 3 */
 4 #include <stdio.h>
 5 #define N 105
 6 #define INF 60000
 7 int G[N][N],n;
 8 typedef struct {
 9     int dist;
10     int data;
11 }Closedge;
12 int ans;
13 void prim(int s){///从s结点查找
14     int flag[N];///标记是否被选中
15     Closedge closedge[N];
16     for(int i = 0; i < N; i++) {
17         flag[i] = 0;
18         closedge[i].dist = G[s][i];
19         closedge[i].data = s;
20     }
21     int m = 0,min;
22     flag[s] = 1;
23     while(m < n - 1){///加n-1个点
24         min = 0;
25         ///选出最小的那个
26         for(int i = 0; i < n; i++){
27             if(closedge[min].dist > closedge[i].dist)
28                 min = i;
29         }
30         ///入选min点
31         flag[min] = 1;
32         closedge[min].dist = INF;
33         ans += G[closedge[min].data][min];
34         ///更新closedge数组
35         for(int j = 0; j < n; j++)
36             ///min与j直接相连
37             ///j点是没有入选的点
38             ///结点min到结点j < closeage.[data]
39             if(G[min][j] < closedge[j].dist && G[min][j]!=0 && !flag[j]){
40                 closedge[j].dist = G[min][j];
41                 closedge[j].data = min;
42             }
43         m++;
44     }
45 }
46 int main(void){
47     while(scanf("%d",&n) != EOF){
48         for(int i = 0; i < n; i++)
49         for(int j = 0; j < n; j++){
50             scanf("%d",&G[i][j]);
51             if(G[i][j] == 0)
52                 G[i][j] = INF;
53         }
54         ans = 0;
55         prim(0);
56         printf("%d\n",ans);
57     }
58     return 0;
59 }