title: Dyck Path
signature: dyckPath :: Integer -> Double
  dyckPath n = 
test_code: import Text.Printf
  import Control.Exception (catch, SomeException)
  import Data.Typeable
  import qualified Data.List as List
  import qualified Data.Map as Map
  import qualified Data.Set as Set
  
  -- SOLUTION CODE
  -- ============================================
  
  PLACEHOLDER_CODE_BODY
  
  -- TESTING CODE 
  -- ============================================
  validateSolution :: Double -> Double -> Bool
  validateSolution actual expected = do
      (abs (actual-expected)) < 1e-09
  
  driver :: Integer -> Double -> String
  driver n expected = do
      if (validateSolution (PLACEHOLDER_FN_NAME n) expected)
          then "PASSED"
      else "FAILED"
  
  main = do
      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) )
  
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 );
  }