Two string - C++ if(a[i] && b[i]) statement

Twostring7.cpp

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include<string>
#include <algorithm>
using namespace std;


int main() {
    int t;
    cin>>t;
    while(t--)
    {
        int a[101]={0},b[101]={0};
        string s1,s2;
        cin>>s1>>s2;
        for(int i=0;i<s1.length();i++)
            a[s1[i]-'a']++;
        for(int i=0;i<s2.length();i++)
            b[s2[i]-'a']++;
        int flag=0;
        for(int i=0;i<26;i++)
            {
                if(a[i] && b[i])
                      flag=1;
        }
        if(flag) cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    return 0;
}