Assignment 7. Huffman Coding

Due Wednesday, December 1 at 11:59 pm

  • Submissions received by the due date receive a small on-time bonus.
  • All students are granted a pre-approved extension or "grace period" of 48 hours after the due date. Late submissions are accepted during the grace period with no penalty.
  • The grace period expires Fri, Dec 3 at 11:59 pm, after which we cannot accept further late submissions.
  • All due dates and submission times are expressed in Pacific time.

The summit of Mount CS106B is now in your sights – many congratulations on the hard work that got you here! The task for Assignment 7 is to write a program that uses the nifty Huffman coding algorithm to compress and decompress files. This program draws upon concepts from across the quarter including use of ADTs, recursive exploration, linked structures, trees, and streaming algorithms and will leverage the powerful skills for effective development, testing, and debugging that you have built up. You'll finish with an impressive piece of software that serves as a great testament to all that you have learned this quarter!

This assignment is to be completed individually. Working in pairs/groups is not permitted.

Learning goals

  • Students will gain practice with constructing, manipulating, and traversing binary trees.
  • Students will be able to synthesize a number of different data structures and algorithms to accomplish an important real-world task.
  • Students will develop understanding of how compression algorithms take advantage of patterns and trends in data to allow for more space-efficient representation.

Assignment parts

This assignment consists of a warmup exercise to get you thinking about the different components of Huffman encoding and a main programming task that asks you to implement the Huffman encoding algorithm.

  • Warmup

    This component consists of some conceptual exercises on Huffman coding, as well as developing some utility functions that you will later use to test your Huffman program.

  • Huffman

    You will implement an end-to-end compression-decompression tool that employs Huffman coding to optimally compress data.

Getting started

As always, we have provided a ZIP of the starter project. Download the zip, extract the files, and double-click the .pro file to open the project in Qt Creator.

📦 Starter code


Here are resources that will be helpful for this assignment:

Getting help

Look for an announcement on the Ed forum for the YEAH session for this assignment. As always, we're here to help you if you get stuck. The Ed forum is open 24/7 for general discussion. Always start by searching first to see if your question has already been asked and answered before making a new post. To troubleshoot a problem with your specific code, your best bet is to bring it to the LaIR helper hours or office hours.


Before you call it done, run through our submit checklist to be sure all your ts are crossed and is dotted. Then upload your completed files to Paperless for grading.

Please submit only the files you edited; for this assignment, these files will be

  • huffman.cpp
  • short_answer.txt
  • secretmessage.txt.huf, an encoded message for your section leader

🏁 Submit to Paperless