title: How To Check If A Given Array Represents A Binary Heap
signature: class Solution {
  
      public bool HowToCheckIfAGivenArrayRepresentsABinaryHeap(List<int> arr, int i, int n) {
test_code: using System;
  using System.Numerics;
  using System.Diagnostics;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Security.Cryptography;
  using System.Web.UI;
  using System.Web.Script.Serialization;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  namespace EvaluatePrediction {
      class TestRunner {
          public bool ValidateSolution(bool actual, bool expected){
              return new JavaScriptSerializer().Serialize(actual) == new JavaScriptSerializer().Serialize(expected);
          }
  
          public string driver(List<int> arr, int i, int n, bool expected){
              try{
                PLACEHOLDER_CLS_NAME solution_cls = new PLACEHOLDER_CLS_NAME();
                bool pred_result = solution_cls.PLACEHOLDER_FN_NAME(arr, i, n); 
                if (ValidateSolution(
                      pred_result,
                      expected)){
                  return "PASSED";
                }
                return "FAILED";
              } 
              catch (Exception exception_obj)
              {
                return exception_obj.GetType().FullName;
              }
          }
          static void Main(string[] args) {
              TestRunner runner = new TestRunner();
              String result;
              result = runner.driver(
                  new List<int>{1, 2, 3, 5, 24, 24, 25, 25, 36, 37, 37, 39, 42, 44, 46, 50, 51, 54, 56, 60, 62, 70, 71, 73, 75, 80, 80, 85, 86, 89, 91, 95, 99}, 0, 18, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-0...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-44, -58, 88, -42, 42, -14, -44, 42, 64, 94, -46, -70, 34, -10, -46, -52, -6, -78, 64, 56, 74, 98, -34, -4, -92, 6, -52, -20, 78, -72, -40}, 0, 27, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-1...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 0, 20, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-2...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{10, 2, 1, 34, 21, 37, 49, 31, 70, 97, 87, 50, 76, 55}, 0, 8, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-3...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-94, -84, -82, -66, -64, -62, -56, -38, -24, -24, -4, 2, 4, 4, 8, 14, 16, 20, 30, 34, 34, 48, 58, 58, 70, 76, 78, 86, 88, 96, 98}, 0, 26, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-4...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0}, 12, 11, 
                  true
              );
              Console.WriteLine(string.Format(
                  "TEST-5...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{5, 20, 30, 5, 10, 21, 5}, 0, 7, 
                  false
              );
              Console.WriteLine(string.Format(
                  "TEST-6...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{50, 20, 30, 5, 10, 21, 5}, 0, 7, 
                  true
              );
              Console.WriteLine(string.Format(
                  "TEST-7...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{50, 20, 30, 5, 10, 21, 5}, 2, 7, 
                  true
              );
              Console.WriteLine(string.Format(
                  "TEST-8...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{50, 20, 30, 5, 10, 21, 5}, 4, 7, 
                  true
              );
              Console.WriteLine(string.Format(
                  "TEST-9...{0}",
                  result)
              );
          }
      }
  }
  
source_py: def how_to_check_if_a_given_array_represents_a_binary_heap(arr, i, n):
      if (i > int(((n - 2) / 2))):
          return True
      if ((arr[i] >= arr[((2 * i) + 1)]) and (arr[i] >= arr[((2 * i) + 2)]) and how_to_check_if_a_given_array_represents_a_binary_heap(arr, ((2 * i) + 1), n) and how_to_check_if_a_given_array_represents_a_binary_heap(arr, ((2 * i) + 2), n)):
          return True
      return False
source_cpp: bool how_to_check_if_a_given_array_represents_a_binary_heap(vector<int> arr, int i, int n) {
    if ( i > ( n - 2 ) / 2 ) return true;
    if ( arr [ i ] >= arr [ 2 * i + 1 ] && arr [ i ] >= arr [ 2 * i + 2 ] && how_to_check_if_a_given_array_represents_a_binary_heap ( arr, 2 * i + 1, n ) && how_to_check_if_a_given_array_represents_a_binary_heap ( arr, 2 * i + 2, n ) ) return true;
    return false;
  }