solution Of 1107. Social Clusters (30)

1107. Social Clusters (30)

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:

Ki: hi[1] hi[2] … hi[Ki]

where Ki (>0) is the number of hobbies, and hi[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:
8
3: 2 7 10
1: 4
2: 5 3
1: 4
1: 3
1: 4
4: 6 8 1 5
1: 4
Sample Output:
3
4 3 1

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结题思路 :
题意要求我们将输出注册用户的用户群。
要求1：利用并查集来处理，将用户兴趣集存在交集的划归到一类；
要求2：并查集部分的需要做距离压缩。

程序步骤：
第一步、将用户的第一个兴趣作为用户最后的兴趣类别；
第二步、将每个用户的兴趣集做一遍并查集；
第三步、对之前每个用户暂存的兴趣类别放入并查集中查询，返回最后的类别；
第四步、根据题目要求的数据输出格式做出一定的调整。

具体程序(AC)如下:

#include <iostream>#include <vector>#include <string>#include <cstring>#include <algorithm>#define maxS 1005using namespace std;vector<int> classify;int parent[maxS];int findRoot(int a){    if(parent[a]==0)        return a;    else//压缩距离的处理        return parent[a]=findRoot(parent[a]);}void unionJoin(int a,int b){    int ra=findRoot(a);    int rb=findRoot(b);    if(ra!=rb)        parent[ra]=rb;}int main(){    int num;    cin>>num;    memset(parent,0,sizeof(parent));    classify.resize(num);    int hobbySize,hobbyStart,hobby;    for(int i=0;i<num;++i)//对兴趣进行分类，对用户进行简单分类    {        cin>>hobbySize;        getchar();        cin>>hobbyStart;        classify[i]=hobbyStart;//粗归类        for(int j=1;j<hobbySize;++j)        {            cin>>hobby;            unionJoin(hobbyStart,hobby);        }    }    for(int i=0;i<num;++i)//对用户进行正确分类        classify[i]=findRoot(classify[i]);//细归类    //其实到这里大体上的计算已经完成了，以下部分是对输出格式的要求做出的修正。      int visited[maxS];    memset(visited,0,sizeof(visited));    for(int i=0;i<num;++i)        ++visited[classify[i]];    vector<int> result;    result.clear();    for(int i=0;i<maxS;++i)        if(visited[i]>0)            result.push_back(visited[i]);    sort(result.begin(),result.end());    reverse(result.begin(),result.end());    cout<<result.size()<<endl;    if(result.size()>0)        cout<<result[0];    for(int i=1;i<result.size();++i)        cout<<" "<<result[i];    cout<<endl;}