Wednesday, July 3, 2024
HomeData ModellingData Structure & AlgorithmRearrange an array to maximize i*arr

Rearrange an array to maximize i*arr[i]

Given an array of N integers, you have to select all of these integers in any order. For every integer you select, you get points equal to the value of: the selected integer * number of integers selected before the current integer. Your task is to maximize these points. 

Note: You can select every integer exactly 1 time.

Examples: 

Input: a = {1, 4, 2, 3, 9} 
Output: 56 
The optimal solution for this array would be select the numbers in the order 1, 2, 3, 4, 9 that gives points 0, 2, 6, 12, 36 respectively and giving a total maximum points of 56.

Input: a = {1, 2, 2, 4, 9} 
Output: 54 
The optimal solution for this array would be select the numbers in the order 1, 2, 2, 4, 9 that gives points 0, 2, 4, 12, 36 respectively and giving a total maximum points of 54. 

The idea is to use Greedy Approach, i.e., maximize the multiplier for the largest element. We sort the given array and start picking elements in this sorted manner, starting with the first element.

Below is the implementation of the above approach:

C++




// C++ program for the Optimal Solution
#include <bits/stdc++.h>
#include <iostream>
using namespace std;
 
    // Function to calculate the maximum points
    // earned by making an optimal selection on
    // the given array
    static int findOptimalSolution(int a[], int N)
    {
        // Sorting the array
        sort(a, a+N);
        // Variable to store the total points earned
        int points = 0;
 
        for (int i = 0; i < N; i++) {
            points += a[i] * i;
        }
        return points;
    }
 
    // Driver code
int main() {
    int a[] = { 1, 4, 2, 3, 9 };
    int N = sizeof(a)/sizeof(a[0]);
        cout<<(findOptimalSolution(a, N));
     
    return 0;
}


Java




// Java program for the Optimal Solution
import java.io.*;
import java.util.*;
 
class GFG {
 
    // Function to calculate the maximum points
    // earned by making an optimal selection on
    // the given array
    static int findOptimalSolution(int[] a, int N)
    {
        // Sorting the array
        Arrays.sort(a);
 
        // Variable to store the total points earned
        int points = 0;
 
        for (int i = 0; i < N; i++) {
            points += a[i] * i;
        }
        return points;
    }
 
    // Driver code
    public static void main(String args[])
    {
        int[] a = { 1, 4, 2, 3, 9 };
        int N = a.length;
        System.out.println(findOptimalSolution(a, N));
    }
}


Python3




# Python3 program for the Optimal Solution
 
# Function to calculate the maximum points
# earned by making an optimal selection on
# the given array
def findOptimalSolution(a, N) :
         
    # Sorting the array
    a.sort() 
     
    # Variable to store the total points earned
    points = 0
   
    for i in range(0, N):
        points += a[i] * i
      
    return points
   
     
if __name__ == "__main__":
     
    a = [1, 4, 2, 3, 9]
    N = len(a)
    print(findOptimalSolution(a, N))


C#




//C# program for the Optimal Solution
using System;
 
public class GFG{
     
        // Function to calculate the maximum points
    // earned by making an optimal selection on
    // the given array
    static int findOptimalSolution(int[]a, int N)
    {
        // Sorting the array
        Array.Sort(a);
 
        // Variable to store the total points earned
        int points = 0;
 
        for (int i = 0; i < N; i++) {
            points += a[i] * i;
        }
        return points;
    }
 
    // Driver code
    static public void Main (){
        int[] a = { 1, 4, 2, 3, 9 };
        int N = a.Length;
        Console.WriteLine(findOptimalSolution(a, N));
    }
//This code is contributed by ajit   
}


PHP




<?php
// PHP program for the Optimal Solution
 
// Function to calculate the maximum
// points earned by making an optimal
// selection on the given array
function findOptimalSolution($a, $N)
{
    // Sorting the array
    sort($a);
 
    // Variable to store the
    // total points earned
    $points = 0;
 
    for ($i = 0; $i < $N; $i++)
    {
        $points += $a[$i] * $i;
    }
    return $points;
}
 
// Driver code
$a = array( 1, 4, 2, 3, 9 );
$N = sizeof($a);
 
echo (findOptimalSolution($a, $N));
 
// This code is contributed by ajit
?>


Javascript




<script>
    // Javascript program for the Optimal Solution
     
    // Function to calculate the maximum points
    // earned by making an optimal selection on
    // the given array
    function findOptimalSolution(a, N)
    {
        // Sorting the array
        a.sort(function(a, b){return a - b});
   
        // Variable to store the total points earned
        let points = 0;
   
        for (let i = 0; i < N; i++) {
            points += a[i] * i;
        }
        return points;
    }
     
    let a = [ 1, 4, 2, 3, 9 ];
    let N = a.length;
    document.write(findOptimalSolution(a, N));
 
</script>


Output

56

Complexity analysis:

  • Time Complexity: O(n log(n))
  • Auxiliary Space: O(1)

Feeling lost in the world of random DSA topics, wasting time without progress? It’s time for a change! Join our DSA course, where we’ll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!

Nango Kalahttps://www.kala.co.za
Experienced Support Engineer with a demonstrated history of working in the information technology and services industry. Skilled in Microsoft Excel, Customer Service, Microsoft Word, Technical Support, and Microsoft Office. Strong information technology professional with a Microsoft Certificate Solutions Expert (Privet Cloud) focused in Information Technology from Broadband Collage Of Technology.
RELATED ARTICLES

LEAVE A REPLY

Please enter your comment!
Please enter your name here

Most Popular

Recent Comments