title: Dyck Path
signature: function dyckPath($n) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return abs($actual - $expected) < 1e-09;
  }
  
  function driver($n, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($n), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        28, 
        263747951750360.03));
      
      printf("TEST-1...%s\n",driver(
        13, 
        742900.0));
      
      printf("TEST-2...%s\n",driver(
        7, 
        429.0));
      
  }
  
  main();
  ?>
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 );
  }