Maximum possible difference of two subsets of an array
Last Updated :
24 Mar, 2023
Given an array of n-integers. The array may contain repetitive elements but the highest frequency of any element must not exceed two. You have to make two subsets such that the difference of the sum of their elements is maximum and both of them jointly contain all elements of the given array along with the most important condition, no subset should contain repetitive elements.
Examples:
Input : arr[] = {5, 8, -1, 4}
Output : Maximum Difference = 18
Explanation :
Let Subset A = {5, 8, 4} & Subset B = {-1}
Sum of elements of subset A = 17, of subset B = -1
Difference of Sum of Both subsets = 17 - (-1) = 18
Input : arr[] = {5, 8, 5, 4}
Output : Maximum Difference = 12
Explanation :
Let Subset A = {5, 8, 4} & Subset B = {5}
Sum of elements of subset A = 17, of subset B = 5
Difference of Sum of Both subsets = 17 - 5 = 12
Before solving this question we have to take care of some given conditions, and they are listed as:
- While building up the subsets, take care that no subset should contain repetitive elements. And for this, we can conclude that all such elements whose frequency are 2, going to be part of both subsets, and hence overall they don’t have any impact on the difference of subset-sum. So, we can easily ignore them.
- For making the difference of the sum of elements of both subset maximum we have to make subset in such a way that all positive elements belong to one subset and negative ones to other subsets.
Algorithm with time complexity O(n2):
for i=0 to n-1
isSingleOccurrence = true;
for j= i+1 to n-1
// if frequency of any element is two
// make both equal to zero
if arr[i] equals arr[j]
arr[i] = arr[j] = 0
isSingleOccurrence = false;
break;
if isSingleOccurrence == true
if (arr[i] > 0)
SubsetSum_1 += arr[i];
else
SubsetSum_2 += arr[i];
return abs(SubsetSum_1 - SubsetSum2)
Implementation:
C++
#include <bits/stdc++.h>
using namespace std;
int maxDiff( int arr[], int n)
{
int SubsetSum_1 = 0, SubsetSum_2 = 0;
for ( int i = 0; i <= n - 1; i++) {
bool isSingleOccurrence = true ;
for ( int j = i + 1; j <= n - 1; j++) {
if (arr[i] == arr[j]) {
isSingleOccurrence = false ;
arr[i] = arr[j] = 0;
break ;
}
}
if (isSingleOccurrence) {
if (arr[i] > 0)
SubsetSum_1 += arr[i];
else
SubsetSum_2 += arr[i];
}
}
return abs (SubsetSum_1 - SubsetSum_2);
}
int main()
{
int arr[] = { 4, 2, -3, 3, -2, -2, 8 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << "Maximum Difference = " << maxDiff(arr, n);
return 0;
}
|
Java
import java .io.*;
public class GFG {
static int maxDiff( int []arr, int n)
{
int SubsetSum_1 = 0 , SubsetSum_2 = 0 ;
for ( int i = 0 ; i <= n - 1 ; i++)
{
boolean isSingleOccurrence = true ;
for ( int j = i + 1 ; j <= n - 1 ; j++)
{
if (arr[i] == arr[j])
{
isSingleOccurrence = false ;
arr[i] = arr[j] = 0 ;
break ;
}
}
if (isSingleOccurrence)
{
if (arr[i] > 0 )
SubsetSum_1 += arr[i];
else
SubsetSum_2 += arr[i];
}
}
return Math.abs(SubsetSum_1 - SubsetSum_2);
}
static public void main (String[] args)
{
int []arr = { 4 , 2 , - 3 , 3 , - 2 , - 2 , 8 };
int n = arr.length;
System.out.println( "Maximum Difference = "
+ maxDiff(arr, n));
}
}
|
Python3
import math
def maxDiff(arr, n) :
SubsetSum_1 = 0
SubsetSum_2 = 0
for i in range ( 0 , n) :
isSingleOccurrence = True
for j in range (i + 1 , n) :
if (arr[i] = = arr[j]) :
isSingleOccurrence = False
arr[i] = arr[j] = 0
break
if (isSingleOccurrence = = True ) :
if (arr[i] > 0 ) :
SubsetSum_1 + = arr[i]
else :
SubsetSum_2 + = arr[i]
return abs (SubsetSum_1 - SubsetSum_2)
arr = [ 4 , 2 , - 3 , 3 , - 2 , - 2 , 8 ]
n = len (arr)
print ( "Maximum Difference = {}"
. format (maxDiff(arr, n)))
|
C#
using System;
public class GFG {
static int maxDiff( int []arr, int n)
{
int SubsetSum_1 = 0, SubsetSum_2 = 0;
for ( int i = 0; i <= n - 1; i++)
{
bool isSingleOccurrence = true ;
for ( int j = i + 1; j <= n - 1; j++)
{
if (arr[i] == arr[j])
{
isSingleOccurrence = false ;
arr[i] = arr[j] = 0;
break ;
}
}
if (isSingleOccurrence)
{
if (arr[i] > 0)
SubsetSum_1 += arr[i];
else
SubsetSum_2 += arr[i];
}
}
return Math.Abs(SubsetSum_1 - SubsetSum_2);
}
static public void Main ()
{
int []arr = { 4, 2, -3, 3, -2, -2, 8 };
int n = arr.Length;
Console.WriteLine( "Maximum Difference = "
+ maxDiff(arr, n));
}
}
|
PHP
<?php
function maxDiff( $arr , $n )
{
$SubsetSum_1 = 0;
$SubsetSum_2 = 0;
for ( $i = 0; $i <= $n - 1; $i ++)
{
$isSingleOccurrence = true;
for ( $j = $i + 1; $j <= $n - 1; $j ++)
{
if ( $arr [ $i ] == $arr [ $j ])
{
$isSingleOccurrence = false;
$arr [ $i ] = $arr [ $j ] = 0;
break ;
}
}
if ( $isSingleOccurrence )
{
if ( $arr [ $i ] > 0)
$SubsetSum_1 += $arr [ $i ];
else
$SubsetSum_2 += $arr [ $i ];
}
}
return abs ( $SubsetSum_1 - $SubsetSum_2 );
}
$arr = array (4, 2, -3, 3, -2, -2, 8);
$n = sizeof( $arr );
echo "Maximum Difference = " , maxDiff( $arr , $n );
?>
|
Javascript
<script>
function maxDiff(arr, n)
{
let SubsetSum_1 = 0, SubsetSum_2 = 0;
for (let i = 0; i <= n - 1; i++)
{
let isSingleOccurrence = true ;
for (let j = i + 1; j <= n - 1; j++)
{
if (arr[i] == arr[j])
{
isSingleOccurrence = false ;
arr[i] = arr[j] = 0;
break ;
}
}
if (isSingleOccurrence)
{
if (arr[i] > 0)
SubsetSum_1 += arr[i];
else
SubsetSum_2 += arr[i];
}
}
return Math.abs(SubsetSum_1 - SubsetSum_2);
}
let arr = [ 4, 2, -3, 3, -2, -2, 8 ];
let n = arr.length;
document.write( "Maximum Difference = "
+ maxDiff(arr, n));
</script>
|
Output
Maximum Difference = 20
Time Complexity O(n2)
Auxiliary Space: O(1)
Algorithm with time complexity O(n log n):
-> sort the array
-> for i =0 to n-2
// consecutive two elements are not equal
// add absolute arr[i] to result
if arr[i] != arr[i+1]
result += abs(arr[i])
// else skip next element too
else
i++;
// special check for last two elements
-> if (arr[n-2] != arr[n-1])
result += arr[n-1]
-> return result;
Implementation:
C++
#include <bits/stdc++.h>
using namespace std;
int maxDiff( int arr[], int n)
{
int result = 0;
sort(arr, arr + n);
for ( int i = 0; i < n - 1; i++) {
if (arr[i] != arr[i + 1])
result += abs (arr[i]);
else
i++;
}
if (arr[n - 2] != arr[n - 1])
result += abs (arr[n - 1]);
return result;
}
int main()
{
int arr[] = { 4, 2, -3, 3, -2, -2, 8 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << "Maximum Difference = " << maxDiff(arr, n);
return 0;
}
|
Java
import java. io.*;
import java .util.*;
public class GFG {
static int maxDiff( int []arr, int n)
{
int result = 0 ;
Arrays.sort(arr);
for ( int i = 0 ; i < n - 1 ; i++)
{
if (arr[i] != arr[i + 1 ])
result += Math.abs(arr[i]);
else
i++;
}
if (arr[n - 2 ] != arr[n - 1 ])
result += Math.abs(arr[n - 1 ]);
return result;
}
static public void main (String[] args)
{
int [] arr = { 4 , 2 , - 3 , 3 , - 2 , - 2 , 8 };
int n = arr.length;
System.out.println( "Maximum Difference = "
+ maxDiff(arr, n));
}
}
|
Python 3
def maxDiff(arr, n):
result = 0
arr.sort()
for i in range (n - 1 ):
if ( abs (arr[i]) ! = abs (arr[i + 1 ])):
result + = abs (arr[i])
else :
pass
if (arr[n - 2 ] ! = arr[n - 1 ]):
result + = abs (arr[n - 1 ])
return result
if __name__ = = "__main__" :
arr = [ 4 , 2 , - 3 , 3 , - 2 , - 2 , 8 ]
n = len (arr)
print ( "Maximum Difference = " ,
maxDiff(arr, n))
|
C#
using System;
public class GFG {
static int maxDiff( int []arr, int n)
{
int result = 0;
Array.Sort(arr);
for ( int i = 0; i < n - 1; i++)
{
if (arr[i] != arr[i + 1])
result += Math.Abs(arr[i]);
else
i++;
}
if (arr[n - 2] != arr[n - 1])
result += Math.Abs(arr[n - 1]);
return result;
}
static public void Main ()
{
int [] arr = { 4, 2, -3, 3, -2, -2, 8 };
int n = arr.Length;
Console.WriteLine( "Maximum Difference = "
+ maxDiff(arr, n));
}
}
|
PHP
<?php
function maxDiff( $arr , $n )
{
$result = 0;
sort( $arr );
for ( $i = 0; $i < $n - 1; $i ++)
{
if ( $arr [ $i ] != $arr [ $i + 1])
$result += abs ( $arr [ $i ]);
else
$i ++;
}
if ( $arr [ $n - 2] != $arr [ $n - 1])
$result += abs ( $arr [ $n - 1]);
return $result ;
}
$arr = array ( 4, 2, -3, 3, -2, -2, 8 );
$n = count ( $arr );
echo "Maximum Difference = "
, maxDiff( $arr , $n );
?>
|
Javascript
<script>
function maxDiff(arr, n)
{
var result = 0;
arr.sort((a,b)=> a-b)
for ( var i = 0; i < n - 1; i++) {
if (arr[i] != arr[i + 1])
result += Math.abs(arr[i]);
else
i++;
}
if (arr[n - 2] != arr[n - 1])
result += Math.abs(arr[n - 1]);
return result;
}
var arr = [ 4, 2, -3, 3, -2, -2, 8 ];
var n = arr.length;
document.write( "Maximum Difference = " + maxDiff(arr, n));
</script>
|
Output
Maximum Difference = 20
Time Complexity: O(n log n)
Auxiliary Space: O(1)
Algorithm with time complexity O(n):
make hash table for positive elements:
for all positive elements(arr[i])
if frequency == 1
SubsetSum_1 += arr[i];
make hash table for negative elements:
for all negative elements
if frequency == 1
SubsetSum_2 += arr[i];
return abs(SubsetSum_1 - SubsetSum2)
Implementation:
C++
#include <bits/stdc++.h>
using namespace std;
int maxDiff( int arr[], int n)
{
unordered_map< int , int > hashPositive;
unordered_map< int , int > hashNegative;
int SubsetSum_1 = 0, SubsetSum_2 = 0;
for ( int i = 0; i <= n - 1; i++)
if (arr[i] > 0)
hashPositive[arr[i]]++;
for ( int i = 0; i <= n - 1; i++)
if (arr[i] > 0 && hashPositive[arr[i]] == 1)
SubsetSum_1 += arr[i];
for ( int i = 0; i <= n - 1; i++)
if (arr[i] < 0)
hashNegative[ abs (arr[i])]++;
for ( int i = 0; i <= n - 1; i++)
if (arr[i] < 0 &&
hashNegative[ abs (arr[i])] == 1)
SubsetSum_2 += arr[i];
return abs (SubsetSum_1 - SubsetSum_2);
}
int main()
{
int arr[] = { 4, 2, -3, 3, -2, -2, 8 };
int n = sizeof (arr) / sizeof (arr[0]);
cout << "Maximum Difference = " << maxDiff(arr, n);
return 0;
}
|
Java
import java.util.*;
class GFG{
public static int maxDiff( int arr[],
int n)
{
HashMap<Integer,
Integer> hashPositive = new HashMap<>();
HashMap<Integer,
Integer> hashNegative = new HashMap<>();
int SubsetSum_1 = 0 ,
SubsetSum_2 = 0 ;
for ( int i = 0 ; i <= n - 1 ; i++)
{
if (arr[i] > 0 )
{
if (hashPositive.containsKey(arr[i]))
{
hashPositive.replace(arr[i],
hashPositive.get(arr[i]) + 1 );
}
else
{
hashPositive.put(arr[i], 1 );
}
}
}
for ( int i = 0 ; i <= n - 1 ; i++)
{
if (arr[i] > 0 &&
hashPositive.containsKey(arr[i]))
{
if (hashPositive.get(arr[i]) == 1 )
{
SubsetSum_1 += arr[i];
}
}
}
for ( int i = 0 ; i <= n - 1 ; i++)
{
if (arr[i] < 0 )
{
if (hashNegative.containsKey(Math.abs(arr[i])))
{
hashNegative.replace(Math.abs(arr[i]),
hashNegative.get(Math.abs(arr[i])) + 1 );
}
else
{
hashNegative.put(Math.abs(arr[i]), 1 );
}
}
}
for ( int i = 0 ; i <= n - 1 ; i++)
{
if (arr[i] < 0 &&
hashNegative.containsKey(Math.abs(arr[i])))
{
if (hashNegative.get(Math.abs(arr[i])) == 1 )
{
SubsetSum_2 += arr[i];
}
}
}
return Math.abs(SubsetSum_1 - SubsetSum_2);
}
public static void main(String[] args)
{
int arr[] = { 4 , 2 , - 3 , 3 ,
- 2 , - 2 , 8 };
int n = arr.length;
System.out.print( "Maximum Difference = " +
maxDiff(arr, n));
}
}
|
Python3
def maxDiff(arr, n):
hashPositive = dict ()
hashNegative = dict ()
SubsetSum_1, SubsetSum_2 = 0 , 0
for i in range (n):
if (arr[i] > 0 ):
hashPositive[arr[i]] = \
hashPositive.get(arr[i], 0 ) + 1
for i in range (n):
if (arr[i] > 0 and arr[i] in
hashPositive.keys() and
hashPositive[arr[i]] = = 1 ):
SubsetSum_1 + = arr[i]
for i in range (n):
if (arr[i] < 0 ):
hashNegative[ abs (arr[i])] = \
hashNegative.get( abs (arr[i]), 0 ) + 1
for i in range (n):
if (arr[i] < 0 and abs (arr[i]) in
hashNegative.keys() and
hashNegative[ abs (arr[i])] = = 1 ):
SubsetSum_2 + = arr[i]
return abs (SubsetSum_1 - SubsetSum_2)
arr = [ 4 , 2 , - 3 , 3 , - 2 , - 2 , 8 ]
n = len (arr)
print ( "Maximum Difference =" , maxDiff(arr, n))
|
C#
using System;
using System.Collections.Generic;
class GFG {
static int maxDiff( int [] arr, int n)
{
Dictionary< int , int > hashPositive =
new Dictionary< int , int >();
Dictionary< int , int > hashNegative =
new Dictionary< int , int >();
int SubsetSum_1 = 0, SubsetSum_2 = 0;
for ( int i = 0; i <= n - 1; i++)
{
if (arr[i] > 0)
{
if (hashPositive.ContainsKey(arr[i]))
{
hashPositive[arr[i]] += 1;
}
else
{
hashPositive.Add(arr[i], 1);
}
}
}
for ( int i = 0; i <= n - 1; i++)
{
if (arr[i] > 0 && hashPositive.ContainsKey(arr[i]))
{
if (hashPositive[arr[i]] == 1)
{
SubsetSum_1 += arr[i];
}
}
}
for ( int i = 0; i <= n - 1; i++)
{
if (arr[i] < 0)
{
if (hashNegative.ContainsKey(Math.Abs(arr[i])))
{
hashNegative[(Math.Abs(arr[i]))] += 1;
}
else
{
hashNegative.Add(Math.Abs(arr[i]), 1);
}
}
}
for ( int i = 0; i <= n - 1; i++)
{
if (arr[i] < 0 &&
hashNegative.ContainsKey(Math.Abs(arr[i])))
{
if (hashNegative[(Math.Abs(arr[i]))] == 1)
{
SubsetSum_2 += arr[i];
}
}
}
return Math.Abs(SubsetSum_1 - SubsetSum_2);
}
static void Main() {
int [] arr = {4, 2, -3, 3, -2, -2, 8};
int n = arr.Length;
Console.WriteLine( "Maximum Difference = " +
maxDiff(arr, n));
}
}
|
Javascript
<script>
function maxDiff(arr,n)
{
let hashPositive = new Map();
let hashNegative = new Map();
let SubsetSum_1 = 0,
SubsetSum_2 = 0;
for (let i = 0; i <= n - 1; i++)
{
if (arr[i] > 0)
{
if (hashPositive.has(arr[i]))
{
hashPositive.set(arr[i],
hashPositive.get(arr[i]) + 1);
}
else
{
hashPositive.set(arr[i], 1);
}
}
}
for (let i = 0; i <= n - 1; i++)
{
if (arr[i] > 0 &&
hashPositive.has(arr[i]))
{
if (hashPositive.get(arr[i]) == 1)
{
SubsetSum_1 += arr[i];
}
}
}
for (let i = 0; i <= n - 1; i++)
{
if (arr[i] < 0)
{
if (hashNegative.has(Math.abs(arr[i])))
{
hashNegative.set(Math.abs(arr[i]),
hashNegative.get(Math.abs(arr[i])) + 1);
}
else
{
hashNegative.set(Math.abs(arr[i]), 1);
}
}
}
for (let i = 0; i <= n - 1; i++)
{
if (arr[i] < 0 &&
hashNegative.has(Math.abs(arr[i])))
{
if (hashNegative.get(Math.abs(arr[i])) == 1)
{
SubsetSum_2 += arr[i];
}
}
}
return Math.abs(SubsetSum_1 - SubsetSum_2);
}
let arr = [4, 2, -3, 3,
-2, -2, 8];
let n = arr.length;
document.write( "Maximum Difference = " +
maxDiff(arr, n));
</script>
|
Output
Maximum Difference = 20
Time Complexity: O(n)
Auxiliary Space: O(n)
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