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c_cpp
2 years ago
994 B
3
Indexable
Never
// Association for Control Over Minds.cpp
#include<iostream>
#include<unordered_map>
#include<unordered_set>
#include<vector>
using namespace std;

using ll = long long;
using um = unordered_map<int, unordered_set<int>>;
const int N = 500005;
int p[N], psize[N];
int t, n, ans, y;
int find(int x){
	if (p[x] != x) p[x] = find(p[x]);
	return p[x];
}
void unionset(int a, int b){
	a = find(a), b = find(b);
	//if (psize[a] >= psize[b]) swap(a, b);
	psize[a] += psize[b];
	p[b] = a;
}
int main(){
	cin >> t;
	for (int i = 1; i < N; i++) p[i] = i, psize[i] = 1;
	while (t--){
		cin >> n;
		um tmp = um{};
		for (int i = 0; i < n; i++){
			cin >> y;
			int x = find(y);
			tmp[x].insert(y);
		}
		for (auto x : tmp) {
			if (x.second.size() != psize[x.first]) n = -1;
			n -= psize[x.first];	
		}

		if (!n){
			ans++;
			for (auto x = tmp.begin(); ++x != tmp.end();)
				unionset(x->first, tmp.begin()->first);
		}
	}
	cout << ans << endl;
	return 0;
}