title: Dyck Path
signature: dyckPath(n) {
test_code: import 'dart:convert';
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(double actual, double expected){
      return (actual - expected).abs() < 1e-09;
  }
  
  String driver(n, double 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(
          28, 
          263747951750360.03)
      }");
  
      print("TEST-1...${driver(
          13, 
          742900.0)
      }");
  
      print("TEST-2...${driver(
          7, 
          429.0)
      }");
  
      return 0;
  }
source_py: def dyck_path(n):
      res = 1
      for i in range(0, n):
          res *= ((2 * n) - i)
          res /= (i + 1)
      return (res / (n + 1))
source_cpp: int dyck_path(unsigned int n) {
    int res = 1;
    for ( int i = 0;
    i < n;
    ++ i ) {
      res *= ( 2 * n - i );
      res /= ( i + 1 );
    }
    return res / ( n + 1 );
  }