Ultra fast mathematicians problem

how to resolve this error

runguard: warning: timelimit exceeded (wall time): aborting command runguard: warning: command terminated with signal 15

#include
#include

using namespace std;

int main()
{
int t;
cin>>t;
while(t–){

string s1, s2;
cin >> s1 >> s2;
for (int i = 0; i < s1.length(); ++i)
{
    if (s1[i] == s2[i])
    {
        s1[i] = '0';
    }
    else
    {
        s1[i] = '1';
    }
}
cout << s1 << endl;

}
return 0;
}

Try to submit ur code. It will pass all testcases.

Test case 0 failed
Wrong answer displayed