title: Count Pairs Difference Equal K
signature: fun countPairsDifferenceEqualK(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(9, 14, 17, 19, 22, 23, 23, 27, 30, 31, 34, 37, 37, 39, 39, 42, 57, 61, 68, 73, 77, 79, 91, 96, 97), 19, 19, 3)
      println("TEST-0...${result}")
      
      result = driver(arrayListOf(-78, -42, 28, -88, 18, -52), 3, 4, 0)
      println("TEST-1...${result}")
      
      result = driver(arrayListOf(0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1), 16, 14, 0)
      println("TEST-2...${result}")
      
      result = driver(arrayListOf(8, 46, 57, 28, 80, 2, 75, 57, 83, 45, 32, 49, 77, 30, 94, 33, 23, 29, 35, 81, 85), 15, 11, 3)
      println("TEST-3...${result}")
      
      result = driver(arrayListOf(-90, -72, -72, -62, -62, -54, -54, -52, -48, -38, -22, -22, -22, -12, -12, -8, -8, -8, -6, -6, -2, 6, 12, 26, 26, 28, 28, 38, 40, 48, 52, 52, 58, 60, 68, 70, 72, 76, 76, 76, 92), 22, 25, 0)
      println("TEST-4...${result}")
      
      result = driver(arrayListOf(0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1), 45, 39, 0)
      println("TEST-5...${result}")
      
      result = driver(arrayListOf(3, 13, 19, 23, 27, 32, 49, 52, 54, 57, 58, 58, 63, 67, 68, 68, 69, 70, 75, 80, 86, 90, 91, 95), 19, 21, 2)
      println("TEST-6...${result}")
      
      result = driver(arrayListOf(-56, 40, -66, 42, 8, -40, -8, -42), 7, 6, 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, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), 16, 28, 0)
      println("TEST-8...${result}")
      
      result = driver(arrayListOf(99, 12, 90, 10, 86, 86, 81, 19, 1, 1, 98, 82, 34, 39, 34, 1, 54, 47, 39, 82, 21, 50, 82, 41, 98, 47, 88, 46, 72, 28, 28, 29, 60, 87, 92, 53, 93, 29, 74, 75, 11, 32, 48, 47, 85, 16, 20), 24, 45, 3)
      println("TEST-9...${result}")
      
          
  }
  
  main()
source_py: def count_pairs_difference_equal_k(arr, n, k):
      count = 0
      for i in range(0, n):
          for j in range((i + 1), n):
              if (((arr[i] - arr[j]) == k) or ((arr[j] - arr[i]) == k)):
                  count += 1
      return count
source_cpp: int count_pairs_difference_equal_k(vector<int> arr, int n, int k) {
    int count = 0;
    for ( int i = 0;
    i < n;
    i ++ ) {
      for ( int j = i + 1;
      j < n;
      j ++ ) if ( arr [ i ] - arr [ j ] == k || arr [ j ] - arr [ i ] == k ) count ++;
    }
    return count;
  }