Find maximum sum of two array elements in Java

Two elements giving the maximum sum in an array means, we have to find two largest array elements which will eventually give the maximum sum possible.

In this article we will see how we can find the maximum sum of two elements in Java.

To show you some instances

The Chinese translation of

Instance-1

is:

Instance-1

Suppose we have the below array

[10, 2, 3, -5, 99, 12, 0, -1]

In this array the largest element is 99 and second largest is 12.

Max sum = 99 12

Therefore, the maximum sum of two elements in this array is 111.

Instance-2

Suppose we have the below array

[556, 10, 259, 874, 123, 453, -96, -54, -2369]

In this array, the largest element is 874, and the second largest element is 556.

Max sum = 874 556

Therefore, the maximum sum of two elements in this array is 1430.

Instance-3

Suppose we have the below array

[55, 10, 29, 74, 12, 45, 6, 5, 269]

In this array, the largest element is 269, and the second largest element is 74.

Max sum= 269 74

Therefore, the maximum sum of two elements in this array is 343.

Algorithm

Algorithm-1

Step 1 − Use a for loop to find the largest and second largest elements in the array.

Step 2 - Find their sum.

Step 3 − Print the sum.

The translation of

Algorithm-2

is:

Algorithm-2

Step 1 − Sort the array elements.

Step 2 −Take the last and second last element of the array.

Step 3 − Find their sum.

Step 4 − Print the sum.

Syntax

To sort the array we need to use the sort( ) method of the Arrays class of java.util package.

Following is the syntax to sort any array in ascending order using the method

<span class="typ">Arrays</span><span class="pun">.</span><span class="pln">sort</span><span class="pun">(</span><span class="pln">array_name</span><span class="pun">);</span>

Where, ‘array_name’ refers to the array that you want to sort.

Multiple methods

We have provided the solution in different approaches.

• Use a for loop to find the largest sum

• Find The Largest Sum Using Arrays.sort

Let’s look at the program and its output one by one.

Method 1: Use for loop

In this approach, we use a for loop to iterate through the array elements to find out the largest and second largest element. These two elements will give the maximum sum.

Example

public class Main {
   public static void main(String[] args) {
      // The array elements
      int arr[] = { 10, 2, 3, -5, 99, 12, 0, -1 };

      // Storing the first element in both variables
      int first = arr[0], second = arr[0];

      // For loop to iterate the elements from 1 to n
      // to find the first largest element
      for (int i = 0; i < arr.length; i++) {

         // If array element is larger than current largest element, then swap
         if (arr[i] > first)
         first = arr[i];
      }

      // For loop to iterate the elements from 1 to n
      // to find the second largest element
      for (int i = 0; i < arr.length; i++) {

         // If array element is larger than current largest element and not equals to
         // largest element, then swap
         if (arr[i] > second && arr[i] != first)
            second = arr[i];
      }

      // Print the sum
      System.out.println("Largest sum = " + (first + second));
      System.out.println("The elements are " + first + " and " + second);
   }
}

Output

Largest sum = 111
The elements are 99 and 12

Approach-2: By Using Arrays.sort

In this method, we use the Arrays.sort() method to sort the array. Then we take the element at the last and penultimate index. Since the array is already sorted, these two elements will give the maximum sum.

Example

import java.util.Arrays;
public class Main {
   public static void main(String[] args) {
      // The array elements
      int arr[] = { 10, 2, 3, -5, 99, 12, 0, -1 };

      // Sort the array using the sort method from array class
      Arrays.sort(arr);

      // Storing the last element as largest and second last element as second largest
      int first = arr[arr.length - 1], second = arr[arr.length - 2];

      // Print the maximum sum
      System.out.println("Maximum sum = " + (first + second));
      System.out.println("The elements are " + first + " and " + second);
   }
}

Output

Maximum sum = 104
The elements are 99 and 12

In this article, we explored different ways to find the two elements in an array that have the maximum sum in Java.

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