title: Count Index Pairs Equal Elements Array
signature: function count_index_pairs_equal_elements_array(arr, n)
test_code: 
  
  -- SOLUTION CODE
  -- ============================================
  PLACEHOLDER_CODE_BODY
  
  -- TESTING CODE 
  -- ============================================
  function isCorrect(actual, expected)
      if type(expected) ~= type(actual) then
          return false
      end
      
      if type(expected) == 'table' then
          for k,v_expected in pairs(expected) do
              
              if actual[k] == nil then
                  return false
              end
              local v_actual = actual[k]
              if not isCorrect(v_actual, v_expected) then
                  return false
              end
              actual[k]=nil
          end
      
          if next(actual) then 
              return false
          end
          return true
      else
          return actual == expected
      end
  end
  
  function validateSolution(actual, expected)
      return isCorrect(actual,expected)
  end
  
  function driver(arr, n, expected)
      local exec_result;
      local status, error_msg = pcall(function () 
          exec_result=PLACEHOLDER_FN_NAME(arr, n) 
      end)
      if status then
          if validateSolution(exec_result,expected) then
              return "PASSED"
          end
          return "FAILED"
      else
          return string.format("ERROR=%s",string.gsub(error_msg,".*:[%d]+: ",""))
      end
  end
      
  function main()
      result = driver({4, 6, 9, 16, 16, 21, 36, 41, 58, 60, 62, 73, 77, 81, 95}, 12, 1)
      print(string.format("TEST-0...%s",result))
  
      result = driver({-86, -72, -26, -34, 18, -62, -66}, 3, 0)
      print(string.format("TEST-1...%s",result))
  
      result = driver({1}, 0, 0)
      print(string.format("TEST-2...%s",result))
  
      result = driver({16}, 0, 0)
      print(string.format("TEST-3...%s",result))
  
      result = driver({-88, -80, -72, -68, -64, -26, 4, 14, 16, 22, 30, 32, 60, 74, 82}, 11, 0)
      print(string.format("TEST-4...%s",result))
  
      result = driver({0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1}, 9, 16)
      print(string.format("TEST-5...%s",result))
  
      result = driver({3, 9, 10, 12, 17, 23, 27, 29, 42, 44, 59, 61, 71, 76, 78, 82, 84, 84, 89, 90, 93, 93, 97, 97}, 15, 0)
      print(string.format("TEST-6...%s",result))
  
      result = driver({68, -40, -46, -20, -64, 90}, 5, 0)
      print(string.format("TEST-7...%s",result))
  
      result = driver({0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 15, 61)
      print(string.format("TEST-8...%s",result))
  
      result = driver({99, 17, 94, 43, 97, 17, 11, 58, 75, 94, 37, 22, 54, 31, 41, 4, 55, 69, 92, 80, 45, 97, 16, 33, 36, 17, 43, 82, 81, 64, 22, 65, 85, 44, 47, 14}, 23, 3)
      print(string.format("TEST-9...%s",result))
  
  end
  
  main()
source_py: def count_index_pairs_equal_elements_array(arr, n):
      ans = 0
      for i in range(0, n):
          for j in range((i + 1), n):
              if (arr[i] == arr[j]):
                  ans += 1
      return ans
source_cpp: int count_index_pairs_equal_elements_array(vector<int> arr, int n) {
    int ans = 0;
    for ( int i = 0;
    i < n;
    i ++ ) for ( int j = i + 1;
    j < n;
    j ++ ) if ( arr [ i ] == arr [ j ] ) ans ++;
    return ans;
  }