title: Nth Even Length Palindrome
signature: function nth_even_length_palindrome(n)
source_py: def nth_even_length_palindrome(n):
      res = n
      for j in range((len(n) - 1), (- 1), (- 1)):
          res += n[j]
      return res
source_cpp: string nth_even_length_palindrome(string n) {
    string res = n;
    for ( int j = n . length ( ) - 1;
    j >= 0;
    -- j ) res += n [ j ];
    return res;
  }