title: Count Pairs Difference Equal K 1
signature: func countPairsDifferenceEqualK1(arr []int, n int, k int) int {
test_code: package main
  
  import (
      "fmt"
      "reflect"
      "math"
      "sort"
  )
  
  // SOLUTION CODE
  // ===================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE
  // ===================================
  func validateSolution(actual int, expected int) bool {
      return reflect.DeepEqual(actual,expected)
  }
  
  func driver(arr []int, n int, k int, expected int) string {
      if validateSolution(PLACEHOLDER_FN_NAME(arr, n, k),expected) {
              return "PASSED"
      }
      return "FAILED"
  
  }
  
  func main() {
  
      // Use imports to avoid undefined errors
      var _ = reflect.DeepEqual
      _ = math.Abs
      _ = sort.Sort
      result := ""
      result = driver([]int{5, 5, 10, 19, 29, 32, 40, 60, 65, 70, 72, 89, 92}, 
  	7, 
  	12, 0)
      fmt.Printf("TEST-0...%s\n", result)
      
      result = driver([]int{-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)
      fmt.Printf("TEST-1...%s\n", result)
      
      result = driver([]int{0, 0, 1}, 
  	1, 
  	1, 0)
      fmt.Printf("TEST-2...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-3...%s\n", result)
      
      result = driver([]int{-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)
      fmt.Printf("TEST-4...%s\n", result)
      
      result = driver([]int{0, 1, 1}, 
  	2, 
  	1, 1)
      fmt.Printf("TEST-5...%s\n", result)
      
      result = driver([]int{11, 43, 50, 58, 60, 68, 75}, 
  	4, 
  	4, 0)
      fmt.Printf("TEST-6...%s\n", result)
      
      result = driver([]int{-80, -56, -10, 0, 6, 8, 24, 42, 52, 86, 88, 94}, 
  	11, 
  	9, 0)
      fmt.Printf("TEST-7...%s\n", result)
      
      result = driver([]int{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)
      fmt.Printf("TEST-8...%s\n", result)
      
      result = driver([]int{4, 7, 9, 9, 14, 34, 34, 36, 50, 54, 80, 81, 99}, 
  	9, 
  	8, 0)
      fmt.Printf("TEST-9...%s\n", result)
      
          
  }
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;
  }