Решение задачи Одинаковые суммы с Codeforces

#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef _DEBUG
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
#endif
	
	int k;
	cin >> k;
	vector<pair<int, pair<int, int>>> a;
	for (int i = 0; i < k; ++i) {
		int n;
		cin >> n;
		vector<int> x(n);
		for (int j = 0; j < n; ++j)
			cin >> x[j];
		int sum = accumulate(x.begin(), x.end(), 0);
		for (int j = 0; j < n; ++j)
			a.push_back(make_pair(sum - x[j], make_pair(i, j)));
	}
	
	stable_sort(a.begin(), a.end());
	for (int i = 0; i < int(a.size()) - 1; ++i) {
		if (a[i].first == a[i + 1].first && (a[i].second.first != a[i + 1].second.first)) {
			cout << "YES" << endl;
			cout << a[i + 1].second.first + 1 << " " << a[i + 1].second.second + 1 << endl;
			cout << a[i].second.first + 1 << " " << a[i].second.second + 1 << endl;
			return 0;
		}
	}
	
	cout << "NO\n";
	
	return 0;
}