Java: Rearrange a given array of unique elements such that every second element of the array is greater than its left and right elements

Java Array: Exercise-61 with Solution

Write a Java program to rearrange a given array of unique elements such that every second element of the array is greater than its left and right elements.

Example:
Input :
nums= { 1, 2, 4, 9, 5, 3, 8, 7, 10, 12, 14 }
Output:
Array with every second element is greater than its left and right elements:
[1, 4, 2, 9, 3, 8, 5, 10, 7, 14, 12]

Sample Solution:

Java Code:

// Import the necessary Java class.
import java.util.Arrays;

// Define a class named 'solution'.
class solution
{
    // A private method to swap two elements in an array.
    private static void swap_nums(int[] nums, int i, int j) {
        int temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }

    // A method to rearrange an array such that every second element is greater
    // than its left and right elements.
    public static void rearrange_Array_nums(int[] nums)
    {
        for (int i = 1; i < nums.length; i += 2)
        {
            // Check if the element to the left is greater and swap if needed.
            if (nums[i - 1] > nums[i]) {
                swap_nums(nums, i - 1, i);
            }

            // Check if the element to the right is greater and swap if needed.
            if (i + 1 < nums.length && nums[i + 1] > nums[i]) {
                swap_nums(nums, i + 1, i);
            }
        }
    }

    public static void main (String[] args)
    {
        int[] nums= { 1, 2, 4, 9, 5, 3, 8, 7, 10, 12, 14 };
        System.out.println("Original array:\n"+Arrays.toString(nums));

        // Rearrange the array so that every second element is greater than its
        // left and right elements.
        rearrange_Array_nums(nums);

        System.out.println("\nArray with every second element is greater than its left and right elements:\n"
                + Arrays.toString(nums));
    }
}

Sample Output:

Original array:
[1, 2, 4, 9, 5, 3, 8, 7, 10, 12, 14]

Array with every second element is greater than its left and right elements:
[1, 4, 2, 9, 3, 8, 5, 10, 7, 14, 12]

Flowchart:

Java Code Editor:

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