title: Count Pairs Difference Equal K
signature: int countPairsDifferenceEqualK(vector<int> arr, int n, int k) {
test_code: #include <algorithm>
  #include <assert.h>
  #include <cstdlib>
  #include <iostream>
  #include <map>
  #include <set>
  #include <string>
  #include <tuple> 
  #include <unordered_map>
  #include <vector>
  #include <math.h>
  #include <cmath>
  #include <bits/stdc++.h>
  #include <numeric>
  #include <functional>
  
  using namespace std;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  bool validateSolution(int actual, int expected){
      return actual == expected;
  }
  
  string driver(vector<int> arr, int n, int k, int expected){
      try
      {
          if (validateSolution(PLACEHOLDER_FN_NAME(arr, n, k), expected)){
              return "PASSED";
          }
          return "FAILED";
      }
      catch (const std::overflow_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::runtime_error& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (const std::exception& exception_obj)
      {
          return typeid(exception_obj).name();
      }
      catch (...)
      {
          return "UNK_ERROR";
      }
  }
  
  int main() {
      string result = "";
  
      result = 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); 
      cout << "TEST-" << 0 << "..."
           <<  result
           << "\n";
  
      result = driver({-78, -42, 28, -88, 18, -52}, 3, 4, 0); 
      cout << "TEST-" << 1 << "..."
           <<  result
           << "\n";
  
      result = driver({0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}, 16, 14, 0); 
      cout << "TEST-" << 2 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 3 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 4 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 5 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 6 << "..."
           <<  result
           << "\n";
  
      result = driver({-56, 40, -66, 42, 8, -40, -8, -42}, 7, 6, 0); 
      cout << "TEST-" << 7 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 8 << "..."
           <<  result
           << "\n";
  
      result = 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); 
      cout << "TEST-" << 9 << "..."
           <<  result
           << "\n";
  
      return 0;
  }
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;
  }