1107. Social Clusters (30)

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1107. Social Clusters (30)

时间限制

1000 ms

内存限制

65536 kB

代码长度限制

16000 B

判题程序

Standard

作者

CHEN, Yue

When register on a social network, you are always asked to specify your hobbies in order to find some potential friends with the same hobbies. A "social cluster" is a set of people who have some of their hobbies in common. You are supposed to find all the clusters.

Input Specification:

Each input file contains one test case. For each test case, the first line contains a positive integer N (<=1000), the total number of people in a social network. Hence the people are numbered from 1 to N. Then N lines follow, each gives the hobby list of a person in the format:

K_i: h_i[1] h_i[2] ... h_i[K_i]

where K_i (>0) is the number of hobbies, and h_i[j] is the index of the j-th hobby, which is an integer in [1, 1000].

Output Specification:

For each case, print in one line the total number of clusters in the network. Then in the second line, print the numbers of people in the clusters in non-increasing order. The numbers must be separated by exactly one space, and there must be no extra space at the end of the line.

Sample Input:

Sample Output:

3
4 3 1

-------------------------------------------------

题意：喜欢同样活动的人属于一个集合，问一共有多少个集合，递减输出每个集合里的人数。

思路：并查集

AC代码：

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <queue>
#include <stack>

using namespace std;

bool comp(int a,int b)
{
    return a>b;
}

int power[1010]={0};
int book[1010]={0};
int father[1010];

int findRoot(int x)//找到集合的根
{
    while(x!=father[x])
    {
        x=father[x];
    }
    return x;
}
void init(int n)//初始化
{
    int i;
    for(i=1;i<=n;i++)
        father[i]=i;
}
void Union(int a,int b)//合并元素a，b所在的集合
{
    int roota,rootb;
    roota=findRoot(a);
    rootb=findRoot(b);
    father[roota]=rootb;
}
int main()
{
    //freopen("in.txt","r",stdin);

    int N;
    cin>>N;
    init(N);
    for(int i=1;i<=N;i++)
    {
        int k;
        scanf("%d:",&k);
        int j;
        for(j=1;j<=k;j++)
        {
            int h;
            cin>>h;
            if(book[h]==0)
            {
                book[h]=i;
            }
            else
            {
                Union(i,book[h]);
            }
        }
    }

    int cou=0;
    for(int i=1;i<=N;i++)
    {
        if(father[i]==i)
            cou++;
    }
    cout<<cou<<"\n";

    for(int i=1;i<=N;i++)
    {
        int t=findRoot(i);
        power[t]++;
    }
    sort(power+1,power+1+N,comp);
    
    printf("%d",power[1]);
    for(int i=2;i<=cou;i++)
    {
        printf(" %d",power[i]);
    }

    return 0;
}

笔记：

1.sort也可以排序数组，递增时候加个comp。

bool comp(int a,int b)
{
return a>b;
}