Question

A non-empty array A consisting of N numeric values is given.
The product of quadruplet(P, Q, R, S) equates to A[P] * A[Q] * A[R]
* A[S]
(0 SP<Q<R<S<N).
For example, array A such that:
A[0] = -3
A[6] = 1
A[1] = 1
A[2] = 2 A[3] = -2
A[4] = 5
A[5] = 6
• (0, 1, 2, 3), product is -3*1*2* -2 = 12
.
(1, 2, 4, 5), product is 1*2*5*6 = 30
• (2, 4, 5, 6), product is 2*5*6* 1 = 60
60 is the product of quadruplets (2, 4, 5, 1), which is maximal
Your goal is to find the maximal product of any quadruplet for
input Array A[]
Write an efficient algorithm for the following assumptions:
N is an integer/float within the range [4..100.0001:​

Answer 1

Explanation:

import java.util.*;

public class HelloWorld{

    public static void main(String []args){

       Scanner sc = new Scanner(System.in);

       int n = sc.nextInt();

       

       int[] arr = new int[n];

       float max_product = 1;

       for(int i = 0; i<n; i++)

       {

           arr[i] = sc.nextInt();

       }

       

       for (int i = 0; i < n - 3; i++)

           for (int j = i + 1; j < n - 2; j++)

               for (int k = j + 1; k < n - 1; k++)

                   for (int l = k + 1; l < n; l++)

                       max_product = Math.max(max_product, arr[i] * arr[j] *  arr[k] * arr[l]);

                                               

       System.out.println(max_product);

    }

}