Two string - C++ - code is very readable -

Twostring14.cpp

#include <iostream>
#include <string>
#include <cstring>
using namespace std;

const int MAXN = 128;
int count1[MAXN], count2[MAXN];
string s1, s2;

void getCount(string s, int arr[]) {
	for (int i = 0; i < s.length(); i++) {
		arr[s[i]]++;
	}
}

bool hasCommon() {
	for (int i = 'a'; i <= 'z'; i++) {
		if (count1[i] && count2[i]) {
			return true;
		}
	}

	return false;
}

int main() {
	int nCases;
	cin >> nCases;

	while (nCases--) {
		memset(count1, 0, sizeof(count1));
		memset(count2, 0, sizeof(count2));
		cin >> s1 >> s2;
		getCount(s1, count1);
		getCount(s2, count2);
		
		if (hasCommon()) {
			cout << "YES" << endl;
		}
		else {
			cout << "NO" << endl;
		}
	}

	return 0;
}