hdu杭电1856 More is better【并查集】

标签：

4
1 2
3 4
5 6
1 6
4
1 2
3 4
5 6
7 8

4
2

Hint
A and B are friends(direct or indirect), B and C are friends(direct or indirect), 
then A and C are also friends(indirect).

 In the first sample {1,2,5,6} is the result.
In the second sample {1,2},{3,4},{5,6},{7,8} are four kinds of answers.
 
 

#include<stdio.h>
#define max 10000000
int per[max+100];
int num[max+100];

int find(int x)//找根节点 
{
	int r;
	r=x;
	while(r!=per[r])
	{
		r=per[r];
	}
	per[x]=r;
	return r;
}
void join(int x ,int y)//连接两根节点 
{
	int fx=find(x);
	int fy=find(y);
	if(fx!=fy)
	{
		per[fx]=fy;
		num[fy]+=num[fx];//当前根节点的元素
	}	
}
int main()
{
	int a,b,m,n,i;
	int t;
	while(~scanf("%d",&t))
	{
		if(t==0)
		{
			printf("1\n");
			continue;
		}
		for(i=1;i<=max;++i)//初始化 
		{
			per[i]=i;
			num[i]=1;		//每个节点只有一个元素，自己本身 
		}	
		n=-1;//为了省时间，	
		while(t--)
		{
			scanf("%d%d",&a,&b);
			if(a>n)
			{
				n=a;
			}
			if(b>n)
			{
				n=b;
			}
			join(a,b);
		}	
		int MAX=0;	
		for(i=1;i<=n;++i)//在这用上 
		{
			if(MAX<num[i]) MAX=num[i];
		}
		printf("%d\n",MAX);
	}
	return 0;
}

hdu杭电1856 More is better【并查集】

标签：

原文地址：http://blog.csdn.net/yuzhiwei1995/article/details/47131421