Problem #
Source: [PAT 1107]
Description #
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: 4Sample Output: #
3
4 3 1Solution #
- 题意 给出你每个人的爱好，有相同爱好的为一个团体，要求你计算每个团体的人数，并按降序输出
- 解法 并查集（PS：不知道什么情况，在for循环的判断语句里得先把后面的算出来 如果直接比较如，x.size()-1 就会有问题）
Code #
#include <iostream>
#include <math.h>
#include <string>
#include <algorithm>
#include <vector>
#define max_size 1001
using namespace std;
vector<int> list[max_size], out;
int n, father[max_size], res[max_size];
int findFather(int x)
{
int t = x;
while (x != father[x])
{
x = father[x];
}
while (t != father[t])
{
int z = t;
t = father[t];
father[z] = x;
}
return x;
}
void Union(int a, int b)
{
int fa = findFather(a), fb = findFather(b);
if (fa != fb)
{
father[fb] = fa;
}
}
int main()
{
int tmp, t;
string s;
cin >> n;
for (int i = 1; i <max_size; i++)
{
father[i] = i;
}
for (int i = 1; i <= n; i++)
{
cin >> tmp >> s;
for (int j = 0; j < tmp; j++)
{
cin >> t;
list[t].push_back(i);
}
}
for (int i = 1; i < max_size; i++)
{
int f = list[i].size() - 1;
for (int j = 0; j < f; j++)
Union(list[i][j], list[i][j + 1]);
}
for (int i = 1; i <= n; i++)
{
res[findFather(i)]++;
}
for (int i = 1; i <= n; i++)
{
if (res[i] > 0)
out.push_back(res[i]);
}
sort(out.begin(), out.end());
for (int i = out.size() - 1; i >= 0; i--)
{
cout << out[i];
if (i != 0)
cout << " ";
}
return 0;
}
