HDU 1162 Eddy's picture(最小生成树）

题目链接

裸最小生成树。 还好数据小，0ms。

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include <math.h>
 5 int o[101],num;
 6 double sum;
 7 struct edge
 8 {
 9     int sv,ev;
10     double w;
11 } p[10000];
12 int cmp(const void *a,const void *b)
13 {
14     return (*(struct edge *)a).w>(*(struct edge *)b).w? 1:-1;
15 }
16 int find(int x)
17 {
18     while(x != o[x])
19     {
20         x = o[x];
21     }
22     return x;
23 }
24 void merge(int x,int y,double w)
25 {
26     x = find(x);
27     y = find(y);
28     if(x != y)
29     {
30         o[x] = y;
31         sum += w;
32         num ++;
33     }
34 }
35 int main()
36 {
37     int i,j,n;
38     double x1[101],y1[101];
39     while(scanf("%d",&n)!=EOF)
40     {
41         sum = 0;
42         for(i = 1; i <= n; i ++)
43             o[i] = i;
44         for(i = 1; i <= n; i ++)
45         {
46             scanf("%lf%lf",&x1[i],&y1[i]);
47         }
48         num = 0;
49         for(i = 1; i <= n-1; i ++)
50             for(j = i+1; j <= n; j ++)
51             {
52                 p[num].sv = i;
53                 p[num].ev = j;
54                 p[num].w = sqrt((x1[i]-x1[j])*(x1[i]-x1[j])+(y1[i]-y1[j])*(y1[i]-y1[j]));
55                 num ++;
56             }
57         qsort(p,num,sizeof(p[0]),cmp);
58         num = 1;
59         for(i = 0;; i ++)
60         {
61             if(num == n)
62                 break;
63             merge(p[i].sv,p[i].ev,p[i].w);
64         }
65         printf("%.2lf\n",sum);
66     }
67     return 0;
68 }

 

posted @ 2012-06-13 16:02  Naix_x  阅读(223)  评论(0)  编辑  收藏  举报