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

BJP5 Exercise 11.13: isUnique

Language/Type: Java Collections Sets and Maps
Author: Marty Stepp (on 2019/09/19)

Write a method isUnique that accepts a Map from strings to strings as a parameter and returns true if no two keys map to the same value (and false if any two or more keys do map to the same value). For example, calling your method on the following map would return true: 

{Marty=Stepp, Stuart=Reges, Jessica=Miller, Amanda=Camp, Hal=Perkins}

Calling it on the following map would return false, because of two mappings for Perkins and Reges: 

{Kendrick=Perkins, Stuart=Reges, Jessica=Miller, Bruce=Reges, Hal=Perkins}

The empty map is considered to be unique, so your method should return true if passed an empty map.

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.