w3resource

Java Array Exercises: 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 java.util.Arrays;

class solution
{
	private static void swap_nums(int[] nums, int i, int j) {
		int t_nums = nums[i];
		nums[i] = nums[j];
		nums[j] = t_nums;
	}

	public static void rearrange_Array_nums(int[] nums)
	{
		for (int i = 1; i < nums.length; i += 2)
		{
			if (nums[i - 1] > nums[i]) {
				swap_nums(nums, i - 1, i);
			}

			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_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:

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

Java Code Editor:

Improve this sample solution and post your code through Disqus

Previous: Write a Java program to shuffle a given array of integers.
Next: Write a Java program to find the equilibrium indices from a given array of integers.

What is the difficulty level of this exercise?



Java: Tips of the Day

Different between parseInt() and valueOf() in java?

Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

Integer k = Integer.valueOf(Integer.parseInt("123"))

Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.

Ref: https://bit.ly/3vRuIPY