title: Count Pairs Difference Equal K
signature: countPairsDifferenceEqualK :: [Integer] -> Integer -> Integer -> Integer
  countPairsDifferenceEqualK arr n k = 
test_code: import Text.Printf
  import Control.Exception (catch, SomeException)
  import Data.Typeable
  import qualified Data.List as List
  import qualified Data.Map as Map
  import qualified Data.Set as Set
  
  -- SOLUTION CODE
  -- ============================================
  
  PLACEHOLDER_CODE_BODY
  
  -- TESTING CODE 
  -- ============================================
  validateSolution :: Integer -> Integer -> Bool
  validateSolution actual expected = do
      actual == expected
  
  
  driver :: [Integer] -> Integer -> Integer -> Integer -> String
  driver arr n k expected = do
      if (validateSolution (PLACEHOLDER_FN_NAME arr n k) expected)
          then "PASSED"
      else "FAILED"
  
  main = do
      printf "TEST-0...%s\n" (driver ([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) )
  
      printf "TEST-1...%s\n" (driver ([-78, -42, 28, -88, 18, -52]) (3) (4) (0) )
  
      printf "TEST-2...%s\n" (driver ([0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1]) (16) (14) (0) )
  
      printf "TEST-3...%s\n" (driver ([8, 46, 57, 28, 80, 2, 75, 57, 83, 45, 32, 49, 77, 30, 94, 33, 23, 29, 35, 81, 85]) (15) (11) (3) )
  
      printf "TEST-4...%s\n" (driver ([-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) )
  
      printf "TEST-5...%s\n" (driver ([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) )
  
      printf "TEST-6...%s\n" (driver ([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) )
  
      printf "TEST-7...%s\n" (driver ([-56, 40, -66, 42, 8, -40, -8, -42]) (7) (6) (0) )
  
      printf "TEST-8...%s\n" (driver ([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) )
  
      printf "TEST-9...%s\n" (driver ([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) )
  
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;
  }