[summer daily question] Luogu p5886 Hello, 2020!

Topic link ：P5886 Hello, 2020! - Luogu | New ecology of computer science education (luogu.com.cn)

Background

The hour hand coincides with the minute hand 「 zero 」 At that moment , The ticking sound announced the arrival of the new year .

In the past year , Impermanence, . In front of the screen, you may have heard it not long ago 「OI」, It may also temporarily end the competition career ; May be at the top of the list , May also bear the loneliness of losing the game alone .

in any case , The past is still the past , The future is still the future .

Start with this topic , Meet you 2020 Well ！

Title Description

Input format

Output format

Examples #1

The sample input #1

4 3 2
2 2 3
1 1
3 1 2 3
2 1 3

Sample output #1

1
2

Tips

AC code:

#include<iostream>
#include<algorithm>
#include<vector>

using namespace std;

const int N = 1e6+10;
int a[N];

int main()
{
	int n,m,p;
	cin>>n>>m>>p;
	while(n--)
	{
		int t;
		cin>>t;
		while(t--)
		{
			int x;
			cin>>x;
			a[x]++;
		}
	}
	vector<int> res;
	for(int i=1;i<=m;i++) //  Note that the range must be  1~m , Otherwise, the test point cannot pass ！！！
		if(a[i]==p)
			res.push_back(i);
			
//	sort(res.begin(),res.end()); //  Put in res The container has been placed from small to large according to the serial number , So there is no need to sort .
	cout<<res.size()<<endl;
	for(int i:res)
		cout<<i<<" "; //  Note the output format ！！！ 

	return 0;
}