This code is wrong answer,in which case it is failing.
#include<iostream>
#include<cstdio>
#define FAST_IO ios_base::sync_with_stdio(false);cin.tie(NULL);
using namespace std;
int main()
{
FAST_IO
int T;
cin>>T;
string s;
while(T--)
{
cin>>s;
if(s[0]!=s[1])
{
if(s.length()==2)
cout<<"YES"<<"\n";
else{
int flag=0;
for(int i=2;i<s.length();i+=2)
{
if((s[0]==s[i] && s[1]==s[i+1]) || (s[0] == s[i]))
{
flag=1;
}
else
{
flag=0;
break;
}
}
if(flag == 1)
cout<<"YES"<<"\n";
else
cout<<"NO"<<"\n";
}
}
else
{
cout<<"NO"<<"\n";
}
}
return 0;
}