1056A - Determine Line - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define cy cout<<"YES"<<endl;
#define cn cout<<"NO"<<endl;
#define c0 cout<<0<<endl;
#define c1 cout<<1<<endl;
#define f(i,a,n) for(int i=a;i<n;i++)
#define pb push_back
#define svec(v) sort(v.begin(),v.end())
#define svrev(v) sort(v.begin(),v.end(),greater<int>())
 
 
int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int t=1;
	// cin>>t;
	while(t--){
		int n;
		cin>>n;
		int temp=n;
		map<int,int> mp;
		while(n--){
			int r;
			cin>>r;
			int a[r]={};
			f(i,0,r){
				cin>>a[i];
				mp[a[i]]++;
			}
		}

		for(auto it:mp){
			if(it.second==temp){
				cout<<it.first<<" ";
			}
		}
		cout<<endl;
	}
	return 0;
}