title: Nth Even Length Palindrome
signature: nthEvenLengthPalindrome(n) {
test_code: import 'dart:convert';
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(String actual, String expected){
      return actual.toString() == expected.toString();
  }
  
  String driver(n, String expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(n), expected)){
              return "PASSED";
          }
          return "FAILED";
      }catch(exception_object){
          return exception_object.runtimeType.toString();
      }
  }
  
  int main() {
  
      print("TEST-0...${driver(
          "lSUhEvxcgfI", 
          "lSUhEvxcgfIIfgcxvEhUSl")
      }");
  
      print("TEST-1...${driver(
          "77329283", 
          "7732928338292377")
      }");
  
      print("TEST-2...${driver(
          "010111111", 
          "010111111111111010")
      }");
  
      print("TEST-3...${driver(
          "Stazb", 
          "StazbbzatS")
      }");
  
      print("TEST-4...${driver(
          "0702", 
          "07022070")
      }");
  
      print("TEST-5...${driver(
          "01111111", 
          "0111111111111110")
      }");
  
      print("TEST-6...${driver(
          "a", 
          "aa")
      }");
  
      print("TEST-7...${driver(
          "rznb", 
          "rznbbnzr")
      }");
  
      return 0;
  }
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;
  }