Two string - unordered_set, letters classes

Twostring8.cpp

#include <iostream>
#include <vector>
#include <algorithm>
#include <limits>
#include <queue>
#include <unordered_map>
#include <unordered_set>
#include <string>

using namespace std;

template<typename T> std::ostream& operator<<(std::ostream& str, const std::vector<T>& v) { str << "["; for(auto n : v) str << n << ", "; str << "]"; return str; }

#define debug(x) cout <<  #x  << ": " << x << endl

int main() {
	cin.sync_with_stdio(false);
	cout.sync_with_stdio(false);

	int t;
	cin >> t;

	while(t--) {
		string s1, s2;
		cin >> s1 >> s2;

		unordered_set<char> letters;
		letters.reserve(s1.size());
		for(auto c : s1) letters.insert(c);
		for(auto c : s2) if(letters.count(c)) {
			cout << "YES\n";
			goto next;
		}

		cout << "NO\n";

next:
		;
	}
}