title: Dyck Path
signature: class Solution {
  
      public Double dyckPath(Integer n) {
test_code: import static java.util.Map.entry;  
  import java.util.*;
  import java.lang.*;
  // TESTING CODE 
  // ============================================
  class QuestionEvaluator {
      public static String validateSolution(Integer n, Double expected){
          try{
              Driver driver = new Driver();
              if (driver.run(n,expected)){
                  return "PASSED";
              }
              return "FAILED";
              
          } catch (Exception exception_obj){
              return exception_obj.getClass().getSimpleName();
          }
  
      }
      public static void main(String[] args) {
          String result;
          result = validateSolution(28, 263747951750360.03);
          System.out.println(String.format("%s%s","TEST-0...",result));    
      
          result = validateSolution(13, 742900.0);
          System.out.println(String.format("%s%s","TEST-1...",result));    
      
          result = validateSolution(7, 429.0);
          System.out.println(String.format("%s%s","TEST-2...",result));    
      
      }
  }
  
  class Driver{
      public boolean run(Integer n, Double expected){
  
          PLACEHOLDER_CLS_NAME sol = new PLACEHOLDER_CLS_NAME();
          return validateSolution(sol.PLACEHOLDER_FN_NAME(n),expected);
      }
      
      public boolean validateSolution(Double actual, Double expected){
          return Math.abs(actual - expected) < 1e-09;
      }
  }
  
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
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 );
  }