POJ 2524 Ubiquitous Religions(并查集）

题目链接

赤裸裸的并查集，搞不懂为什么POJ计划里，会用分治做。。

 1 #include <stdio.h>
 2 #include <string.h>
 3 #define N 50001
 4 int o[N];
 5 int find(int x)
 6 {
 7     int r,t;
 8     r = x;
 9     while(x != o[x])
10     x = o[x];
11     while(r != x)
12     {
13         t = o[r];
14         o[r] = x;
15         r = t;
16     }
17     return x;
18 }
19 void merge(int x,int y)
20 {
21     x = find(x);
22     y = find(y);
23     if(x != y)
24     o[x] = y;
25 }
26 int main()
27 {
28     int n,m,i,sv,ev,num = 0,sum;
29     while(scanf("%d%d",&n,&m)!=EOF)
30     {
31         if(n == 0&&m == 0)break;
32         num ++;
33         for(i = 1;i <= n;i ++)
34         o[i] = i;
35         for(i = 1;i <= m;i ++)
36         {
37             scanf("%d%d",&sv,&ev);
38             merge(sv,ev);
39         }
40         printf("Case %d: ",num);
41         sum = 0;
42         for(i = 1;i <= n;i ++)
43         {
44             if(o[i] == i)
45             sum ++;
46         }
47         printf("%d\n",sum);
48     }
49     return 0;
50 }
posted @ 2012-06-30 15:54  Naix_x  阅读(151)  评论(0)  编辑  收藏  举报