Problem Set 3: Game of Fifteen


  1. Watch Week 3’s lecture.

  2. Search and sort some numbers.

  3. Implement the Game of Fifteen.

  4. Submit your code.

  5. Submit a form.


For help with Week 3 and Problem Set 3:

  • Attend Doug’s and Rob’s walkthrough on Wed 9/21, 1pm – 2:30pm, in Sanders.

  • Watch Zamyla’s walkthroughs herein.

  • Attend your TF’s section (or another if you have a conflict).

  • Post questions and search answers in CS50 Discuss.

  • Attend individual TFs' and CAs' office hours at HSA.

  • Attend course-wide office hours:

    • Wed 9/21, 9pm – 11pm, Widener

    • Thu 9/22, 9pm – 11pm, Widener

    • Sun 9/25, 3pm – 5pm, SOCH


  • Use help50 as needed.

  • Use eprintf as needed.

  • Use debug50 as needed.

Getting Started

Alright, here we go again!

Log into and execute


within a terminal window to make sure your workspace is up-to-date.

Next, execute

mkdir ~/workspace/pset3/

at your prompt in order to make a directory called pset3 in your workspace directory.

Now execute

cd ~/workspace/pset3/

and your prompt should resemble the below.

~/workspace/pset3/ $

What to Do

  1. Implement either of:

    • Find, less comfortable

    • Find, more comfortable

  2. Implement Game of Fifteen

How to Submit

Step 1 of 2

  • Update your IDE:

  • Submit find:

    cd ~/workspace/pset3/find/
    submit50 find
  • Submit fifteen:

    cd ~/workspace/pset3/fifteen/
    submit50 fifteen

To confirm that your code was submitted properly, visit If you do, you should be able to click on your GitHub repository and then if you click on Branches you should see a branch for find and a branch for fifteen. If you click on those branches to reveal the files within, you should see your uploaded code.

Step 2 of 2

This was Problem Set 3.