Due Date: Wednesday of week 15

The following guidelines are expected for all homework submissions:

• All homework must be typed. Homework which is not typed will be returned ungraded and will be subject to the late homework guidelines as set out on the syllabus page. PLEASE DO NOT scribble something on lined paper and rip it out of your spiral notebook — hanging chads went out with the presidential election in 2000.
• I don't care too much about what font you use or how large your margins are; however, you might want to check out a monospaced font for typing code, as it will be easy to see the indentations.
• Speaking of indenting, PLEASE DON'T USE TABS TO INDENT YOUR CODE. Tabs can often get interpreted differently by different computers, peripherals, and applications, and could make code that is nicely formatted on *your* computer look all over the map on *my* computer or in my editor. USE SPACES INSTEAD. You can set up almost every modern text editor to insert spaces whenever you press the TAB key, or you can simply pound the spacebar.
• On assignments 1, 2, and 3, WORK BY YOURSELF. On assignments 4 and 5, WORK WITH A PARTNER. I can't stress this enough; part of this policy is don't split up the work – WORK TOGETHER on the assignment. This activity mimics an industry code development model called pair programming which is part of the Extreme Programming software development method. Feel free to collaborate in your pairs as much as you want, doing the entire assignment together.
• DO NOT share your work between groups. Doing so will count as plagiarism. If you wish to discuss solutions with another group over coffee in the Lair, that's fine as long as it is kept at the conceptual level and you don't share your code between groups. Each group needs to turn in its own version of the solutions.
• You only need to turn in ONE COPY per group.
• MAKE SURE YOUR GITHUB REPO IS PRIVATE [for reasons explained on the syllabus page and in class].
• Submit your homework through GitHub, in your repository, to which I must be a contributor or have otherwise been allowed access. I cannot evaluate what I cannot see!

Problems for Assignment #5

Learning Outcomes: 1) implementing the tree traversals; 2) implementing a priority queue data structure using a heap data structure; 3) implementing a hash table that uses linear probing; 4) writing your own hashing method

This problem set has two problems from chapter 11, one problem from chapter 9, and one problem from chapter 12. You will be working with tree traversals, heaps, and hashes for this assignment. Your task is to complete the following problems using the programs specified in each one. As always, when you are finished and ready to submit your work, do so in your repo. MAKE SURE YOUR CODE MODULES ALL COMPILE FROM THE COMMAND LINE! Here are the problems:

1. [This is a review problem to help you get ready for learning about graphs.] Write a method that does an in–order traversal of a tree. It should display all the items in the proper order. Remember that in–order means you visit the left sub–tree, then the current node, then the right sub–tree.
2. Implement the PriorityQ class in the PriorityQ.java program [Listing 4.6] using a heap instead of an array. You should be able to use the Heap class in the heap.java program [Listing 12.1] without modification. Make it a descending queue [largest item is removed].
3. Implement a linear probe hash table that stores strings. You'll need a hash function that converts a string to an index number; see the section Hashing Strings in chapter 11. Assume the strings will be lowercase words, so 26 characters will suffice.
4. Write a hash function to implement a digit-folding approach in the hash function [as described in the Hash Functions section of chapter 11]. Your program should work for any array size and any key length. Use linear probing. Accessing a group of digits in a number may be easier than you think. Does it matter if the array size is not a multiple of 10?