title: Maximum Sum Pairs Specific Difference
signature: class Solution {
  
      public int MaximumSumPairsSpecificDifference(List<int> arr, int n, int k) {
test_code: using System;
  using System.Numerics;
  using System.Diagnostics;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Security.Cryptography;
  using System.Web.UI;
  using System.Web.Script.Serialization;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  namespace EvaluatePrediction {
      class TestRunner {
          public bool ValidateSolution(int actual, int expected){
              return new JavaScriptSerializer().Serialize(actual) == new JavaScriptSerializer().Serialize(expected);
          }
  
          public string driver(List<int> arr, int n, int k, int expected){
              try{
                PLACEHOLDER_CLS_NAME solution_cls = new PLACEHOLDER_CLS_NAME();
                int pred_result = solution_cls.PLACEHOLDER_FN_NAME(arr, n, k); 
                if (ValidateSolution(
                      pred_result,
                      expected)){
                  return "PASSED";
                }
                return "FAILED";
              } 
              catch (Exception exception_obj)
              {
                return exception_obj.GetType().FullName;
              }
          }
          static void Main(string[] args) {
              TestRunner runner = new TestRunner();
              String result;
              result = runner.driver(
                  new List<int>{48, 53, 67, 78, 78, 93, 95}, 6, 4, 
                  156
              );
              Console.WriteLine(string.Format(
                  "TEST-0...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-70, -32, -2, 18, 30, 32, 52, 70, 72, 88}, 8, 8, 
                  62
              );
              Console.WriteLine(string.Format(
                  "TEST-1...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{0, 0, 0, 0, 0, 0, 0, 0, 0, 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, 1, 1}, 37, 31, 
                  10
              );
              Console.WriteLine(string.Format(
                  "TEST-2...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{2, 3, 5, 5, 6, 10, 12, 13, 13, 16, 23, 23, 34, 36, 39, 40, 42, 45, 45, 47, 51, 51, 52, 56, 57, 58, 60, 60, 60, 60, 61, 63, 67, 68, 71, 73, 75, 80, 80, 82, 84, 86, 86, 86, 86, 89, 90, 98, 99}, 31, 37, 
                  1083
              );
              Console.WriteLine(string.Format(
                  "TEST-3...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-84, -56, 68, 78}, 3, 3, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-4...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1}, 14, 9, 
                  5
              );
              Console.WriteLine(string.Format(
                  "TEST-5...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{1, 2, 3, 9, 12, 12, 16, 17, 18, 19, 20, 21, 21, 26, 29, 42, 44, 45, 48, 48, 48, 54, 54, 55, 60, 63, 63, 64, 64, 67, 67, 68, 69, 74, 78, 78, 79, 83, 95, 95, 95, 96, 97, 99}, 27, 42, 
                  849
              );
              Console.WriteLine(string.Format(
                  "TEST-6...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{-92, -58, -56, -48, -42, -16, -14, 28, 40, 42, 54, 60, 64}, 9, 8, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-7...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{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, 1}, 21, 19, 
                  9
              );
              Console.WriteLine(string.Format(
                  "TEST-8...{0}",
                  result)
              );result = runner.driver(
                  new List<int>{25, 64, 96}, 1, 1, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-9...{0}",
                  result)
              );
          }
      }
  }
  
source_py: def maximum_sum_pairs_specific_difference(arr, N, K):
      arr.sort()
      dp = ([0] * N)
      dp[0] = 0
      for i in range(1, N):
          dp[i] = dp[(i - 1)]
          if ((arr[i] - arr[(i - 1)]) < K):
              if (i >= 2):
                  dp[i] = max(dp[i], ((dp[(i - 2)] + arr[i]) + arr[(i - 1)]))
              else:
                  dp[i] = max(dp[i], (arr[i] + arr[(i - 1)]))
      return dp[(N - 1)]
source_cpp: int maximum_sum_pairs_specific_difference(vector<int> arr, int N, int K) {
    sort(arr.begin(), arr.end());
    int dp [ N ];
    dp [ 0 ] = 0;
    for ( int i = 1;
    i < N;
    i ++ ) {
      dp [ i ] = dp [ i - 1 ];
      if ( arr [ i ] - arr [ i - 1 ] < K ) {
        if ( i >= 2 ) dp [ i ] = max ( dp [ i ], dp [ i - 2 ] + arr [ i ] + arr [ i - 1 ] );
        else dp [ i ] = max ( dp [ i ], arr [ i ] + arr [ i - 1 ] );
      }
    }
    return dp [ N - 1 ];
  }