Important Notice:

Practice-It will be discontinued as of November 1st, 2024. After this date, the website will remain online for a transitional period, but login will be restricted to University of Washington NetID authentication. This marks the next phase towards the platform's full retirement. Thank you for your use and support of the application over the years.

If you are looking for an alternative, a similar tool, CodeStepByStep, was developed independently by the original author of Practice-It, and is available at codestepbystep.com**

logo Practice-It logo

Main Page → Problems → Solve a Problem

BJP3 Exercise 14.7: reverseHalf

Language/Type: Java Collections Stacks and Queues
Author: Robert Baxter (on 2013/04/01)

Write a method reverseHalf that reverses the order of half of the elements of a Queue of integers. Your method should reverse the order of all the elements in odd-numbered positions (position 1, 3, 5, etc.) assuming that the first value in the queue has position 0. For example, if the queue originally stores this sequence of numbers when the method is called:

index: 0  1  2  3  4  5   6   7
front [1, 8, 7, 2, 9, 18, 12, 0] back

- it should store the following values after the method finishes executing:

index: 0  1  2  3   4  5  6   7
front [1, 0, 7, 18, 9, 2, 12, 8] back

Notice that numbers in even positions (positions 0, 2, 4, 6) have not moved. That sub-sequence of numbers is still: (1, 7, 9, 12). But notice that the numbers in odd positions (positions 1, 3, 5, 7) are now in reverse order relative to the original. In other words, the original sub-sequence: (8, 2, 18, 0) - has become: (0, 18, 2, 8). You may use a single stack as auxiliary storage.

Type your solution here:


This is a method problem. Write a Java method as described. Do not write a complete program or class; just the method(s) above.

You must log in before you can solve this problem.


Log In

If you do not understand how to solve a problem or why your solution doesn't work, please contact your TA or instructor.
If something seems wrong with the site (errors, slow performance, incorrect problems/tests, etc.), please

Is there a problem? Contact a site administrator.