poj 1258 -- Agri-Net

 1 /*======================================================================
 2  *           Author :   kevin
 3  *         Filename :   AgriNet.cpp
 4  *       Creat time :   2014-07-09 15:55
 5  *      Description :
 6 ========================================================================*/
 7 #include <iostream>
 8 #include <algorithm>
 9 #include <cstdio>
10 #include <cstring>
11 #include <queue>
12 #include <cmath>
13 #define clr(a,b) memset(a,b,sizeof(a))
14 #define M 200
15 #define INF 0x7f7f7f7f
16 using namespace std;
17 int c[M][M],dis[M];
18 int prim(int n)
19 {
20     bool vis[M];
21     int i,j,k,sum = 0;
22     for(i = 0; i < n; i++){
23         dis[i] = c[0][i];
24         vis[i] = false;
25     }
26     vis[0] = true;
27     for(i = 1; i < n; i++){
28         int _min = INF;
29         j = 0;
30         for(k = 0; k < n; k++){
31             if(_min > dis[k] && !vis[k]){
32                 _min = dis[k];
33                 j = k;
34             }
35         }
36         vis[j] = true;
37         sum += dis[j];
38         for(k = 0; k < n; k++){
39             if(dis[k] > c[j][k] && !vis[k]){
40                 dis[k] = c[j][k];
41             }
42         }
43     }
44     return sum;
45 }
46 int main()
47 {
48     int n;
49     while(scanf("%d",&n)!=EOF){
50         clr(c,0);
51         int value;
52         for(int i = 0; i < n; i++){
53             for(int j = 0; j <n; j++){
54                 scanf("%d",&value);
55                 c[i][j] = value;
56             }
57         }
58         int ans = prim(n);
59         printf("%d\n",ans);
60     }
61 }