HDU1301+prim

最小生成树。。。。

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 1 /*
 2 prim
 3 */
 4 #include<stdio.h>
 5 #include<string.h>
 6 #include<stdlib.h>
 7 #include<algorithm>
 8 #include<iostream>
 9 #include<queue>
10 #include<vector>
11 #include<map>
12 #include<math.h>
13 typedef long long ll;
14 //typedef __int64 int64;
15 const int maxn = 105;
16 const int maxm = 1005;
17 const int inf = 0x7FFFFFFF;
18 const double pi = acos(-1.0);
19 const double eps = 1e-8;
20 using namespace std;
21 
22 int mat[ maxn ][ maxn ];
23 int vis[ maxn ],dis[ maxn ];
24 
25 void prim( int n ){
26     for( int i=0;i<n;i++ ){
27         vis[ i ] = 0;
28         dis[ i ] = mat[ 0 ][ i ];
29     }
30     int res = 0;
31     vis[ 0 ] = 1;
32     for( int i=0;i<n;i++ ){
33         int k,fmin;
34         fmin = inf;
35         for( int j=0;j<n;j++ ){
36             if( vis[j]==0&&fmin>dis[ j ] ){
37                 fmin = dis[ j ];
38                 k = j;
39             }
40         }
41         if( fmin==inf ) break;
42         vis[ k ] = 1;
43         res += fmin;
44         for( int j=0;j<n;j++ ){
45             if( vis[ j ]==0&&dis[ j ]>mat[ k ][ j ] ){
46                 dis[ j ] = mat[ k ][ j ];
47             }
48         }
49     }
50     printf("%d\n",res);
51 }    
52 
53 int main(){
54     int n;
55     char a[ 4 ],b[ 4 ];
56     int k,cost;
57     while( scanf("%d",&n)==1,n ){
58         //memset( mat,0,sizeof( mat ) );
59         for( int i=0;i<n;i++ )
60             for( int j=0;j<n;j++ )
61                 mat[i][j] = inf;
62         for( int i=0;i<n-1;i++ ){
63             scanf("%s",a);
64             scanf("%d",&k);
65             while( k-- ){
66                 scanf("%s",b);
67                 scanf("%d",&cost);
68                 mat[ a[0]-'A' ][ b[0]-'A' ] = mat[ b[0]-'A' ][ a[0]-'A' ] = cost;
69             }
70             //prim( n );
71         }
72         prim( n );
73     }
74     return 0;
75 }

 

posted @ 2013-05-04 16:49  xxx0624  阅读(265)  评论(0)  编辑  收藏  举报