1867B - XOR Palindromes - CodeForces Solution

/* ۝ وَأَنْ لَيْسَ لِلإِنسَانِ إِلَّا مَا سَعَى ۝ وَأَنَّ سَعْيَهُ سَوْفَ يُرَى ۝ ثُمَّ يُجْزَاهُ الْجَزَاءَ الأَوْفَى ۝ */

#include <iostream>
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define IO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define ll long long
using namespace __gnu_pbds;
using namespace std;
template<typename T> using ordered_set = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
const ll INF=1e18;
const int N =1e6+5;
const int dx[8] = {0, 0, 1, -1, 1, 1, -1, -1};
const int dy[8] = {1, -1, 0, 0, 1, -1, 1, -1};



int main()
{
IO;
int t;
cin>>t;
while(t--){
int n;
string s;
ll com=0;
cin>>n;
cin>>s;
vector<char>arr(n+1,'0');
for(int i=0;i<n/2;i++){
  if(s[i]!=s[n-i-1])com++;
}
for(int i=com;i<=n;i+=(1+(n%2==0))){

if(n-i>=i)arr[i]='1',arr[n-i]='1';

}
for(int i=0;i<=n;i++)
cout<<arr[i];
cout<<'\n';

}



}