title: Elements To Be Added So That All Elements Of A Range Are Present In Array
signature: class Solution {
  
      public int ElementsToBeAddedSoThatAllElementsOfARangeArePresentInArray(List<int> arr, 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(int actual, int expected){
              return new JavaScriptSerializer().Serialize(actual) == new JavaScriptSerializer().Serialize(expected);
          }
  
          public string driver(List<int> arr, int n, int expected){
              try{
                PLACEHOLDER_CLS_NAME solution_cls = new PLACEHOLDER_CLS_NAME();
                int pred_result = solution_cls.PLACEHOLDER_FN_NAME(arr, 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>{4, 4, 5, 7, 7, 9, 13, 15, 18, 19, 25, 27, 27, 29, 32, 36, 48, 51, 53, 53, 55, 65, 66, 67, 72, 74, 74, 76, 77, 79, 80, 81, 82, 83, 83, 86, 87, 97, 98, 98, 99}, 30, 
                  51
              );
              Console.WriteLine(string.Format(
                  "TEST-0...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-90, -90, -88, -84, -84, -84, -80, -74, -52, -26, -26, -16, -8, 6, 14, 16, 34, 64, 72, 92, 94}, 17, 
                  112
              );
              Console.WriteLine(string.Format(
                  "TEST-1...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{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, 1}, 24, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-2...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{10, 12, 12, 13, 13, 23, 25, 26, 29, 32, 39, 43, 43, 54, 62, 79, 92}, 14, 
                  34
              );
              Console.WriteLine(string.Format(
                  "TEST-3...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-94, -86, -72, -64, -64, -58, -56, -56, -56, -56, -54, -54, -52, -42, -42, -40, -36, -32, -28, -22, -20, -18, -12, -8, -6, -4, 0, 2, 4, 10, 16, 30, 32, 48, 48, 60, 70, 74, 76, 84}, 35, 
                  115
              );
              Console.WriteLine(string.Format(
                  "TEST-4...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{0, 0, 0, 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}, 29, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-5...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{4, 5, 8, 12, 16, 16, 17, 20, 20, 23, 26, 26, 27, 28, 32, 34, 40, 40, 41, 41, 44, 45, 47, 49, 51, 52, 54, 57, 60, 62, 63, 64, 66, 68, 69, 70, 71, 76, 77, 80, 80, 80, 90, 91, 92, 94, 96, 98, 99}, 42, 
                  42
              );
              Console.WriteLine(string.Format(
                  "TEST-6...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-98, -92, -92, -92, -92, -86, -78, -74, -72, -68, -60, -52, -48, -48, -46, -46, -44, -40, -38, -26, -18, 2, 4, 4, 10, 14, 14, 16, 20, 38, 48, 48, 50, 56, 60, 66, 74, 76, 80, 84, 88, 96, 96, 96}, 37, 
                  144
              );
              Console.WriteLine(string.Format(
                  "TEST-7...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{0, 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, 1, 1}, 17, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-8...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{49, 66, 84}, 2, 
                  16
              );
              Console.WriteLine(string.Format(
                  "TEST-9...{0}",
                  result)
              );
          }
      }
  }
  
source_py: def elements_to_be_added_so_that_all_elements_of_a_range_are_present_in_array(arr, n):
      count = 0
      arr.sort()
      for i in range(0, (n - 1)):
          if ((arr[i] != arr[(i + 1)]) and (arr[i] != (arr[(i + 1)] - 1))):
              count += ((arr[(i + 1)] - arr[i]) - 1)
      return count
source_cpp: int elements_to_be_added_so_that_all_elements_of_a_range_are_present_in_array(vector<int> arr, int n) {
    int count = 0;
    sort(arr.begin(), arr.end());
    for ( int i = 0;
    i < n - 1;
    i ++ ) if ( arr [ i ] != arr [ i + 1 ] && arr [ i ] != arr [ i + 1 ] - 1 ) count += arr [ i + 1 ] - arr [ i ] - 1;
    return count;
  }