# Split array into two subarrays such that difference of their sum is minimum

• Difficulty Level : Medium
• Last Updated : 27 May, 2021

Given an integer array arr[], the task is to split the given array into two subarrays such that the difference between their sum is minimum.

Examples:

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Input: arr[] = {7, 9, 5, 10}
Output: 1
Explanation: The difference between the sum of the subarrays {7, 9} and {5, 10} is equal to [16 â€“ 15] = 1, which is the minimum possible.

Input: arr[] = {6, 6, 6}
Output: 6

Naive Approach: The idea is to use the Prefix and Suffix Sum array technique. Generate the prefix sum array and the suffix sum array of the given array. Now, iterate over the array and print the minimum difference between prefix_sum[i] and suffix_sum[i+1], for any index i ( 0 <= i <= N – 1) from the array.
Time Complexity: O(N)
Auxiliary Space: O(N)

Below is the implementation of the above approach:

## C++

 `// C++ program for the above approach``#include ``using` `namespace` `std;` `// Function to return minimum difference``// between two subarray sums``int` `minDiffSubArray(``int` `arr[], ``int` `n)``{` `    ``// To store prefix sums``    ``int` `prefix_sum[n];` `    ``// Generate prefix sum array``    ``prefix_sum[0] = arr[0];` `    ``for``(``int` `i = 1; i < n; i++)``        ``prefix_sum[i] = prefix_sum[i - 1] +``                               ``arr[i];` `    ``// To store suffix sums``    ``int` `suffix_sum[n];` `    ``// Generate suffix sum array``    ``suffix_sum[n - 1] = arr[n - 1];` `    ``for``(``int` `i = n - 2; i >= 0; i--)``        ``suffix_sum[i] = suffix_sum[i + 1] +``                               ``arr[i];` `    ``// Stores the minimum difference``    ``int` `minDiff = INT_MAX;` `    ``// Traverse the given array``    ``for``(``int` `i = 0; i < n - 1; i++)``    ``{``        ` `        ``// Calculate the difference``        ``int` `diff = ``abs``(prefix_sum[i] -``                       ``suffix_sum[i + 1]);` `        ``// Update minDiff``        ``if` `(diff < minDiff)``            ``minDiff = diff;``    ``}` `    ``// Return minDiff``    ``return` `minDiff;``}` `// Driver Code``int` `main()``{``    ` `    ``// Given array``    ``int` `arr[] = { 7, 9, 5, 10 };` `    ``// Length of the array``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);` `    ``cout << minDiffSubArray(arr, n);``}` `// This code is contributed by code_hunt`

## Java

 `// Java Program for above approach``import` `java.util.*;``import` `java.lang.*;` `class` `GFG {` `    ``// Function to return minimum difference``    ``// between two subarray sums``    ``static` `int` `minDiffSubArray(``int` `arr[], ``int` `n)``    ``{` `        ``// To store prefix sums``        ``int``[] prefix_sum = ``new` `int``[n];` `        ``// Generate prefix sum array``        ``prefix_sum[``0``] = arr[``0``];` `        ``for` `(``int` `i = ``1``; i < n; i++)``            ``prefix_sum[i]``                ``= prefix_sum[i - ``1``] + arr[i];` `        ``// To store suffix sums``        ``int``[] suffix_sum = ``new` `int``[n];` `        ``// Generate suffix sum array``        ``suffix_sum[n - ``1``] = arr[n - ``1``];` `        ``for` `(``int` `i = n - ``2``; i >= ``0``; i--)``            ``suffix_sum[i]``                ``= suffix_sum[i + ``1``] + arr[i];` `        ``// Stores the minimum difference``        ``int` `minDiff = Integer.MAX_VALUE;` `        ``// Traverse the given array``        ``for` `(``int` `i = ``0``; i < n - ``1``; i++) {` `            ``// Calculate the difference``            ``int` `diff``                ``= Math.abs(prefix_sum[i]``                           ``- suffix_sum[i + ``1``]);` `            ``// Update minDiff``            ``if` `(diff < minDiff)``                ``minDiff = diff;``        ``}` `        ``// Return minDiff``        ``return` `minDiff;``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Given array``        ``int``[] arr = { ``7``, ``9``, ``5``, ``10` `};` `        ``// Length of the array``        ``int` `n = arr.length;` `        ``System.out.println(``            ``minDiffSubArray(arr, n));``    ``}``}`

## Python3

 `# Python3 program for the above approach``import` `sys` `# Function to return minimum difference``# between two subarray sums``def` `minDiffSubArray(arr, n):` `    ``# To store prefix sums``    ``prefix_sum ``=` `[``0``] ``*` `n` `    ``# Generate prefix sum array``    ``prefix_sum[``0``] ``=` `arr[``0``]` `    ``for` `i ``in` `range``(``1``, n):``        ``prefix_sum[i] ``=` `(prefix_sum[i ``-` `1``] ``+``                                ``arr[i])` `    ``# To store suffix sums``    ``suffix_sum ``=` `[``0``] ``*` `n` `    ``# Generate suffix sum array``    ``suffix_sum[n ``-` `1``] ``=` `arr[n ``-` `1``]` `    ``for` `i ``in` `range``(n ``-` `2``, ``-``1``, ``-``1``):``        ``suffix_sum[i] ``=` `(suffix_sum[i ``+` `1``] ``+``                                ``arr[i])` `    ``# Stores the minimum difference``    ``minDiff ``=` `sys.maxsize` `    ``# Traverse the given array``    ``for` `i ``in` `range``(n ``-` `1``):` `        ``# Calculate the difference``        ``diff ``=` `abs``(prefix_sum[i] ``-``                   ``suffix_sum[i ``+` `1``])` `        ``# Update minDiff``        ``if` `(diff < minDiff):``            ``minDiff ``=` `diff` `    ``# Return minDiff``    ``return` `minDiff` `# Driver Code``if` `__name__ ``=``=` `'__main__'``:``    ` `    ``# Given array``    ``arr ``=` `[ ``7``, ``9``, ``5``, ``10` `]` `    ``# Length of the array``    ``n ``=` `len``(arr)` `    ``print``(minDiffSubArray(arr, n))` `# This code is contributed by mohit kumar 29`

## C#

 `// C# program for the above approach``using` `System;``class` `GFG{` `// Function to return minimum difference``// between two subarray sums``static` `int` `minDiffSubArray(``int` `[]arr,``                           ``int` `n)``{   ``  ``// To store prefix sums``  ``int``[] prefix_sum = ``new` `int``[n];` `  ``// Generate prefix sum array``  ``prefix_sum[0] = arr[0];` `  ``for``(``int` `i = 1; i < n; i++)``    ``prefix_sum[i] = prefix_sum[i - 1] +``                    ``arr[i];` `  ``// To store suffix sums``  ``int``[] suffix_sum = ``new` `int``[n];` `  ``// Generate suffix sum array``  ``suffix_sum[n - 1] = arr[n - 1];` `  ``for``(``int` `i = n - 2; i >= 0; i--)``    ``suffix_sum[i] = suffix_sum[i + 1] +``                    ``arr[i];` `  ``// Stores the minimum difference``  ``int` `minDiff = ``int``.MaxValue;` `  ``// Traverse the given array``  ``for``(``int` `i = 0; i < n - 1; i++)``  ``{``    ``// Calculate the difference``    ``int` `diff = Math.Abs(prefix_sum[i] -``                        ``suffix_sum[i + 1]);` `    ``// Update minDiff``    ``if` `(diff < minDiff)``      ``minDiff = diff;``    ``}` `    ``// Return minDiff``    ``return` `minDiff;``}` `// Driver Code``public` `static` `void` `Main(String[] args)``{   ``    ``// Given array``    ``int``[] arr = {7, 9, 5, 10};` `    ``// Length of the array``    ``int` `n = arr.Length;` `    ``Console.WriteLine(minDiffSubArray(arr, n));``}``}` `// This code is contributed by Amit Katiyar`

## Javascript

 ``

Output:
`1`

Efficient Approach: To optimize the above approach, the idea is to calculate the total sum of the array elements. Now, iterate over the array and calculate the prefix sum of the array and find the minimum difference between the prefix sum and the difference between total sum and the prefix sum for any index of the array, i.e.,

Maximum difference between sum of subarrays = ( prefix_sum – (total_sum – prefix_sum) )

Below is the implementation of the above approach:

## C++

 `// C++ program for above approach``#include ``using` `namespace` `std;` `// Function to return minimum difference``// between sum of two subarrays``int` `minDiffSubArray(``int` `arr[], ``int` `n)``{``    ` `    ``// To store total sum of array``    ``int` `total_sum = 0;` `    ``// Calculate the total sum``    ``// of the array``    ``for``(``int` `i = 0; i < n; i++)``        ``total_sum += arr[i];` `    ``// Stores the prefix sum``    ``int` `prefix_sum = 0;` `    ``// Stores the minimum difference``    ``int` `minDiff = INT_MAX;` `    ``// Traverse the given array``    ``for``(``int` `i = 0; i < n - 1; i++)``    ``{``        ``prefix_sum += arr[i];` `        ``// To store minimum difference``        ``int` `diff = ``abs``((total_sum -``                       ``prefix_sum) -``                       ``prefix_sum);` `        ``// Update minDiff``        ``if` `(diff < minDiff)``            ``minDiff = diff;``    ``}` `    ``// Return minDiff``    ``return` `minDiff;``}` `// Driver code``int` `main()``{``    ` `    ``// Given array``    ``int` `arr[] = { 7, 9, 5, 10 };` `    ``// Length of the array``    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr[0]);` `    ``cout << minDiffSubArray(arr, n) << endl;` `    ``return` `0;``}` `// This code is contributed by divyeshrabadiya07`

## Java

 `// Java Program for above approach``import` `java.util.*;``import` `java.lang.*;` `class` `GFG {` `    ``// Function to return minimum difference``    ``// between sum of two subarrays``    ``static` `int` `minDiffSubArray(``int` `arr[], ``int` `n)``    ``{``        ``// To store total sum of array``        ``int` `total_sum = ``0``;` `        ``// Calculate the total sum``        ``// of the array``        ``for` `(``int` `i = ``0``; i < n; i++)``            ``total_sum += arr[i];` `        ``// Stores the prefix sum``        ``int` `prefix_sum = ``0``;` `        ``// Stores the minimum difference``        ``int` `minDiff = Integer.MAX_VALUE;` `        ``// Traverse the given array``        ``for` `(``int` `i = ``0``; i < n - ``1``; i++) {` `            ``prefix_sum += arr[i];` `            ``// To store minimum difference``            ``int` `diff``                ``= Math.abs((total_sum``                            ``- prefix_sum)``                           ``- prefix_sum);` `            ``// Update minDiff``            ``if` `(diff < minDiff)``                ``minDiff = diff;``        ``}` `        ``// Return minDiff``        ``return` `minDiff;``    ``}` `    ``// Driver Code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Given array``        ``int``[] arr = { ``7``, ``9``, ``5``, ``10` `};` `        ``// Length of the array``        ``int` `n = arr.length;` `        ``System.out.println(``            ``minDiffSubArray(arr, n));``    ``}``}`

## Python3

 `# Python3 program for the above approach``import` `sys` `# Function to return minimum difference``# between sum of two subarrays``def` `minDiffSubArray(arr, n):``    ` `    ``# To store total sum of array``    ``total_sum ``=` `0` `    ``# Calculate the total sum``    ``# of the array``    ``for` `i ``in` `range``(n):``        ``total_sum ``+``=` `arr[i]` `    ``# Stores the prefix sum``    ``prefix_sum ``=` `0` `    ``# Stores the minimum difference``    ``minDiff ``=` `sys.maxsize` `    ``# Traverse the given array``    ``for` `i ``in` `range``(n ``-` `1``):``        ``prefix_sum ``+``=` `arr[i]` `        ``# To store minimum difference``        ``diff ``=` `abs``((total_sum ``-``                   ``prefix_sum) ``-``                   ``prefix_sum)` `        ``# Update minDiff``        ``if` `(diff < minDiff):``            ``minDiff ``=` `diff` `    ``# Return minDiff``    ``return` `minDiff` `# Driver code``    ` `# Given array``arr ``=` `[ ``7``, ``9``, ``5``, ``10` `]` `# Length of the array``n ``=` `len``(arr)` `print``(minDiffSubArray(arr, n))` `# This code is contributed by code_hunt`

## C#

 `// C# Program for above approach``using` `System;``class` `GFG{` `// Function to return minimum difference``// between sum of two subarrays``static` `int` `minDiffSubArray(``int` `[]arr,``                           ``int` `n)``{``  ``// To store total sum of array``  ``int` `total_sum = 0;` `  ``// Calculate the total sum``  ``// of the array``  ``for` `(``int` `i = 0; i < n; i++)``    ``total_sum += arr[i];` `  ``// Stores the prefix sum``  ``int` `prefix_sum = 0;` `  ``// Stores the minimum difference``  ``int` `minDiff = ``int``.MaxValue;` `  ``// Traverse the given array``  ``for` `(``int` `i = 0; i < n - 1; i++)``  ``{``    ``prefix_sum += arr[i];` `    ``// To store minimum difference``    ``int` `diff = Math.Abs((total_sum -``                         ``prefix_sum) -``                         ``prefix_sum);` `    ``// Update minDiff``    ``if` `(diff < minDiff)``      ``minDiff = diff;``  ``}` `  ``// Return minDiff``  ``return` `minDiff;``}` `// Driver Code``public` `static` `void` `Main(String[] args)``{``  ``// Given array``  ``int``[] arr = {7, 9, 5, 10};` `  ``// Length of the array``  ``int` `n = arr.Length;` `  ``Console.WriteLine(``          ``minDiffSubArray(arr, n));``}``}` `// This code is contributed by Rajput-Ji`

## Javascript

 ``
Output:
`1`

Time Complexity: O(N)
Auxiliary Space: O(1)

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