title: Count Pairs Difference Equal K 1
signature: fun countPairsDifferenceEqualK1(arr: ArrayList<Int>, n: Int, k: Int): Int {
test_code: package main
  
  import kotlin.text.*
  import kotlin.math.*
  
  
  // SOLUTION CODE
  // ===================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE
  // ===================================
  fun validateSolution(actual:Int, expected:Int):Boolean{
    return actual.equals(expected)
  }
  fun driver(arr: ArrayList<Int>, n: Int, k: Int, expected:Int):String {
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME(arr, n, k), expected)) {
                return "PASSED"
        }
        return "FAILED"
      } catch (e: Exception){
        return e::class.simpleName as String
      }
  
  }
  
  fun main() {
      var result: String = ""
      result = driver(arrayListOf(5, 5, 10, 19, 29, 32, 40, 60, 65, 70, 72, 89, 92), 7, 12, 0)
      println("TEST-0...${result}")
      
      result = driver(arrayListOf(-98, -90, -88, -82, -80, -78, -74, -74, -72, -62, -58, -58, -56, -52, -48, -46, -38, -38, -30, -12, -10, 4, 8, 8, 14, 22, 24, 26, 36, 40, 40, 48, 56, 58, 58, 58, 60, 62, 64, 68, 68, 74, 84), 24, 36, 7)
      println("TEST-1...${result}")
      
      result = driver(arrayListOf(0, 0, 1), 1, 1, 0)
      println("TEST-2...${result}")
      
      result = driver(arrayListOf(1, 7, 13, 14, 16, 29, 34, 42, 44, 49, 59, 62, 65, 66, 70, 71, 73, 73, 76, 80, 96, 96), 12, 16, 1)
      println("TEST-3...${result}")
      
      result = driver(arrayListOf(-98, -88, -58, -56, -48, -34, -22, -18, -14, -14, -8, -4, -2, 2, 18, 38, 42, 46, 54, 68, 70, 90, 94, 96, 98), 23, 22, 4)
      println("TEST-4...${result}")
      
      result = driver(arrayListOf(0, 1, 1), 2, 1, 1)
      println("TEST-5...${result}")
      
      result = driver(arrayListOf(11, 43, 50, 58, 60, 68, 75), 4, 4, 0)
      println("TEST-6...${result}")
      
      result = driver(arrayListOf(-80, -56, -10, 0, 6, 8, 24, 42, 52, 86, 88, 94), 11, 9, 0)
      println("TEST-7...${result}")
      
      result = driver(arrayListOf(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), 29, 30, 0)
      println("TEST-8...${result}")
      
      result = driver(arrayListOf(4, 7, 9, 9, 14, 34, 34, 36, 50, 54, 80, 81, 99), 9, 8, 0)
      println("TEST-9...${result}")
      
          
  }
  
  main()
source_py: def count_pairs_difference_equal_k_1(arr, n, k):
      count = 0
      arr.sort()
      l = 0
      r = 0
      while (r < n):
          if ((arr[r] - arr[l]) == k):
              count += 1
              l += 1
              r += 1
          elif ((arr[r] - arr[l]) > k):
              l += 1
          else:
              r += 1
      return count
source_cpp: int count_pairs_difference_equal_k_1(vector<int> arr, int n, int k) {
    int count = 0;
    sort(arr.begin(), arr.end());
    int l = 0;
    int r = 0;
    while ( r < n ) {
      if ( arr [ r ] - arr [ l ] == k ) {
        count ++;
        l ++;
        r ++;
      }
      else if ( arr [ r ] - arr [ l ] > k ) l ++;
      else r ++;
    }
    return count;
  }