WA in the problem string reverse

help
1

https://www.codechef.com/viewsolution/58997286

#include <bits/stdc++.h>
using namespace std;

int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);

int t;
cin>>t;
while(t--){
    string s; cin>>s;
    int j=0;
    string r=s;
    reverse(r.begin(), r.end());
    if(s==r){
        cout<<0<<endl;
    }
    else{
    for(int i=s.length()-1;i>=s.length()/2;i--){
        if(s[i]!=s[j]){
            cout<<i<<endl;
            break;
        }
        j++;
    }
    }
}
return 0;

}