HDOJ 1856 More is better

          此题与典型的并查集不同的是，此题要求输出每棵树上节点的个数，所以要考虑的是如何处理节点个数的问题。最后逐个遍历相对于10000000个数据来说显然不是个好方法。仍然是牺牲空间换时间的思想，在‘并’和‘查’的同时将树中的节点个数记录到父节点中。由于数据量较大，所以考虑使用路径压缩。此题中要求了最终至少要有一个(or there is only one boy left)所以记录最大点数的起始值要从1开始才好。参考代码如下：

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 1 #include    
 2 #include    
 3 unsigned value[10000001];  
 4 unsigned maxRecord[10000001];  
 5 unsigned maxValue;  
 6 unsigned find(unsigned v)  
 7 {  
 8     unsigned temp=v;  
 9     while (value[v]!=-1)  
10     {  
11         v=value[v];  
12     }  
13     unsigned j;  
14     while (temp!=v)//路径压缩   
15     {  
16         j=value[temp];  
17         value[temp]=v;  
18         temp=j;  
19     }  
20     return v;  
21 }  
22 void unionSet(unsigned x,unsigned y)  
23 {  
24     unsigned px=find(x);  
25     unsigned py=find(y);  
26     if(px==py)  
27         return ;  
28     value[py]=px;  
29     maxRecord[px]+=maxRecord[py];  
30     if(maxRecord[px]>maxValue)  
31         maxValue=maxRecord[px];  
32 }  
33 int main()  
34 {  
35     //freopen("More is better.txt","r",stdin);   
36   
37     unsigned num,fValue,sValue;  
38     while(scanf("%u",&num)!=EOF)  
39     {  
40         memset(value,-1,sizeof(value));  
41         for (int i=0;i<10000001;i++)  
42             maxRecord[i]=1;  
43         maxValue=1;//设置起始值   
44         for (unsigned i=0;i45         {  
46             scanf("%u%u",&fValue,&sValue);  
47             unionSet(fValue,sValue);  
48         }  
49         printf("%u\n",maxValue);  
50     }  
51 }  

转载于:https://www.cnblogs.com/AdaByron/archive/2011/09/18/2200974.html