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

partition

Language/Type: Java arrays
Author: Marty Stepp

Write a method named partition that accepts an array of integers a and an integer element value v as its parameters, and rearranges ("partitions") the array's elements so that all its elements of a that are less than v occur before all elements that are greater than v. The exact order of the elements is unimportant so long as all elements less than v appear before all elements greater than v. For example, if your method were passed the following array: 

int[] a = {15, 1, 6, 12, -3, 4, 8, -7, 21, 2, 30, -1, 9};
partition(a, 5);

One acceptable ordering of the elements after the call would be: 

{-1, 1, 2, -7, -3, 4, 8, 12, 21, 6, 30, 15, 9}

Hint: Your method will need to rearrange the elements of the array, which will involve swapping various elements from less desirable indexes to more desirable ones.

You may assume that the array contains no duplicates and does not contain the element value v itself. You may not use Arrays.sort, Collections.sort, or any other pre-defined sorting algorithm from the Java Class Libraries or textbook to solve this problem. You also may not use a String to solve this problem.

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.