hdu 3172 Virtual Friends(加权并查集)

原创于 2017-09-01 19:11:02 发布 · 289 阅读

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本文介绍了一种在线社交网络中计算个人社交圈规模的方法。针对互为好友的关系，通过输入新建立的朋友关系，实时更新并输出每个人社交网络的总人数。

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Virtual Friends

Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 9579 Accepted Submission(s): 2793

Problem Description

These days, you can do all sorts of things online. For example, you can use various websites to make virtual friends. For some people, growing their social network (their friends, their friends' friends, their friends' friends' friends, and so on), has become an addictive hobby. Just as some people collect stamps, other people collect virtual friends.

Your task is to observe the interactions on such a website and keep track of the size of each person's network.

Assume that every friendship is mutual. If Fred is Barney's friend, then Barney is also Fred's friend.

Input

Input file contains multiple test cases.
The first line of each case indicates the number of test friendship nest.
each friendship nest begins with a line containing an integer F, the number of friendships formed in this frindship nest, which is no more than 100 000. Each of the following F lines contains the names of two people who have just become friends, separated by a space. A name is a string of 1 to 20 letters (uppercase or lowercase).

Output

Whenever a friendship is formed, print a line containing one integer, the number of people in the social network of the two people who have just become friends.

Sample Input

      
       1
3
Fred Barney
Barney Betty
Betty Wilma

Sample Output

Source

University of Waterloo Local Contest 2008.09

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chenrui

题意：

A B 两人交友

问朋友圈的大小

因为多组数据，每组数据分为T小组

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
#include<map>
#define N 100002
using namespace std;
map<string,int>m;
int pre[N];
int num[N];
void init()
{
    for(int i=1; i<=N; i++)pre[i]=i,num[i]=1;
}
int Find(int x)
{
    if(pre[x]!=x)
        return pre[x]=Find(pre[x]);
    return x;
}
void Merge(int x,int y)
{
    int X=Find(x);
    int Y=Find(y);
    if(X!=Y)
        pre[X]=Y,num[Y]+=num[X];
    printf("%d\n",num[Y]);
}
int main()
{
    int T;
    while(scanf("%d",&T)==1)
    {
        while(T--)
        {
            int n;
            string a,b;
            scanf("%d",&n);
            init();
            m.clear();
            int c=0;
            for(int i=1; i<=n; i++)
            {
                cin>>a>>b;
                if(!m[a])
                    m[a]=++c;
                if(!m[b])
                    m[b]=++c;
                Merge(m[a],m[b]);
            }
        }
    }
}