Given an array arr[] ( 1-based indexing ) consisting of N integers, the task is to find the minimum sum of the absolute difference between all pairs of array elements by decrementing and incrementing any pair of elements by 1 any number of times.
Examples:
Input: arr[] = {1, 2, 3}
Output: 0
Explanation:
Modify the array elements by performing the following operations:
- Choose the pairs of element (arr[1], arr[3]) and incrementing and decrementing the pairs modifies the array to {2, 2, 2}.
After the above operations, the sum of the absolute differences is |2 – 2| + |2 – 2| + |2 – 2| = 0. Therefore, print 0.
Input: arr[] = {0, 1, 0, 1}
Output: 4
Approach: The given problem can be solved by using a Greedy Approach. It can be observed that to minimize the sum of the absolute difference between every pair of array elements arr[], the idea to make every array element closed to each other. Follow the steps below to solve the problem:
- Find the sum of the array elements arr[] and store it in a variable, say sum.
- Now, if the value of sum % N is 0, then print 0 as all the array elements can be made equal and the resultant value of the expression is always 0. Otherwise, find the value of sum % N and store it in a variable, say R.
- Now, if all the array elements are sum/N, then we can make R number of array elements as 1 and the rest of the array elements as 0 to minimize the resultant value.
- After the above steps, the minimum sum of the absolute difference is given by R*(N – R).
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <bits/stdc++.h> using namespace std; // Function to find the minimum value // of the sum of absolute difference // between all pairs of arrays int minSumDifference( int ar[], int n) { // Stores the sum of array elements int sum = 0; // Find the sum of array element for ( int i = 0; i < n; i++) sum += ar[i]; // Store the value of sum%N int rem = sum % n; // Return the resultant value return rem * (n - rem); } // Driver Code int main() { int arr[] = { 3, 6, 8, 5, 2, 1, 11, 7, 10, 4 }; int N = sizeof (arr) / sizeof ( int ); cout << minSumDifference(arr, N); return 0; } |
Java
// Java program for the above approach class GFG { // Function to find the minimum value // of the sum of absolute difference // between all pairs of arrays public static int minSumDifference( int ar[], int n) { // Stores the sum of array elements int sum = 0 ; // Find the sum of array element for ( int i = 0 ; i < n; i++) sum += ar[i]; // Store the value of sum%N int rem = sum % n; // Return the resultant value return rem * (n - rem); } // Driver Code public static void main(String args[]) { int [] arr = { 3 , 6 , 8 , 5 , 2 , 1 , 11 , 7 , 10 , 4 }; int N = arr.length; System.out.println(minSumDifference(arr, N)); } } // This code is contributed by gfgking. |
Python3
# Python 3 program for the above approach # Function to find the minimum value # of the sum of absolute difference # between all pairs of arrays def minSumDifference(ar, n): # Stores the sum of array elements sum = 0 # Find the sum of array element for i in range (n): sum + = ar[i] # Store the value of sum%N rem = sum % n # Return the resultant value return rem * (n - rem) # Driver Code if __name__ = = '__main__' : arr = [ 3 , 6 , 8 , 5 , 2 , 1 , 11 , 7 , 10 , 4 ] N = len (arr) print (minSumDifference(arr, N)) # This code is contributed by ipg2016107. |
C#
// C# program for the above approach using System; class GFG{ // Function to find the minimum value // of the sum of absolute difference // between all pairs of arrays public static int minSumDifference( int [] ar, int n) { // Stores the sum of array elements int sum = 0; // Find the sum of array element for ( int i = 0; i < n; i++) sum += ar[i]; // Store the value of sum%N int rem = sum % n; // Return the resultant value return rem * (n - rem); } // Driver Code public static void Main() { int [] arr = { 3, 6, 8, 5, 2, 1, 11, 7, 10, 4 }; int N = arr.Length; Console.Write(minSumDifference(arr, N)); } } // This code is contributed by sanjoy_62 |
Javascript
<script> // JavaScript program for the above approach // Function to find the minimum value // of the sum of absolute difference // between all pairs of arrays function minSumDifference(ar, n) { // Stores the sum of array elements let sum = 0; // Find the sum of array element for (let i = 0; i < n; i++) sum += ar[i]; // Store the value of sum%N let rem = sum % n; // Return the resultant value return rem * (n - rem); } // Driver Code let arr = [3, 6, 8, 5, 2, 1, 11, 7, 10, 4]; let N = arr.length; document.write(minSumDifference(arr, N)); </script> |
21
Time Complexity: O(N)
Auxiliary Space: O(1)
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