hdu3172 Virtual Friends

1
3
Fred Barney
Barney Betty
Betty Wilma

2
3
4

这题可以用并查集+map来做，注意可能输入的两个字符串相同。


#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<map>
#include<string>
using namespace std;
int pre[100010],num[100010];
int find(int x)
{
	int i,j=x,r=x;
	while(r!=pre[r])r=pre[r];
	while(j!=pre[j]){
		i=pre[j];
		pre[j]=r;
		j=i;
	}
	return r;
}


int main()
{
	int T,n,m,i,j,index,a,b,t1,t2,sum;
	char s1[30],s2[30];
	while(scanf("%d",&T)!=EOF)
	{while(T--)
	{
		map<string,int>hash;
		hash.clear();
		index=1;
		scanf("%d",&n);
		for(i=1;i<=100005;i++){
			pre[i]=i;num[i]=1;
		}
		for(i=1;i<=n;i++){
			scanf("%s%s",s1,s2);
			if(hash[s1]==0)hash[s1]=index++;
			if(hash[s2]==0)hash[s2]=index++;
			t1=find(hash[s1]);
			t2=find(hash[s2]);
			if(t1==t2)printf("%d\n",num[t1]);
			else{
				pre[t1]=t2;
				num[t2]=num[t2]+num[t1];
				printf("%d\n",num[t2]);
			}
		}
	}
	}
	return 0;
}