学步园

water~~~~

简单的并查集，查出有几个集合即可

#include<stdio.h>
#define max(a,b) a>b?a:b
#define min(a,b) a<b?a:b
int father[10000001],vis[10000001],root[10000001];
void init(){
	for(int i=1;i<=10000000;father[i]=i,vis[i++]=0);
}
int findfather(int x){
	if(father[x]!=x)father[x]=findfather(father[x]);
	return father[x];
}
void merge(int a,int b){
	int x,y;
	x=findfather(a); y=findfather(b);
	if(x!=y)father[x]=y;
}
int main(){
	int i,j,k,n,mini,maxi,a,b,x,y,cnt,maxsum;
	while(~scanf("%d",&n)){
		if(n==0){ 
			printf("1/n");continue; 
		}
		init();
		mini=99999999; maxi=-1;
		for(i=1;i<=n;i++){
			scanf("%d%d",&a,&b);
			x=min(a,b); y=max(a,b);
			if(x<mini) mini=x;
			if(y>maxi) maxi=y;
			vis[a]=vis[b]=1;
			merge(a,b);
		}
		for(j=0,i=mini;i<=maxi;i++){
			if(vis[i]==1 && findfather(i)==i)
				root[j++]=i;
		}
		maxsum=0;
		for(i=0;i<j;i++){
			cnt=0;
			for(k=mini;k<=maxi;k++)if(father[k]==root[i])cnt++;
			if(cnt>maxsum)maxsum=cnt;
		}
		printf("%d/n",maxsum);
	}
	return 0;
}