CSC207.01 2014S, Class 46: Pause for Breath
===========================================

_Overview_

* Preliminaries.
    * Admin.
    * Upcoming work.
    * Extra credit.
    * Questions.
* Project stuff.
    * Possible extensions to the project.
    * More notes on submitted work.
    * Planning presentations.
* Implementing heaps.
* Heapsort.
* Doing better?

Preliminaries
-------------

### Admin

* Sugar!
* Mentor session tonight at 7 pm in 3821.
* It's not clear if I'll have time to review any of the other projects.
  We'll continue to talk about code and other issues.
* I need two graders for next semester who can do detailed comments.
  Yes, I will provide training.
* Please download the heap lab code (particularly if there's time at
  the end of class).
  <https://github.com/Grinnell-CSC207/heaps>

### Upcoming Work

* Reading for Wednesday: No reading.  
* Today's writeup: No writeup.
* Part 2 of the project is due Friday at 10:30 p.m.  (No, I'm not updating
  the Web page.)

### Extra Credit

* One pride week activity.
* Math extra Thursday: Sphere Packing.
* CS Table Friday: Heartbleed.
* Iowater project April 26 - Tag drains.  Mail iowater@grinnell.edu for details.

### Questions

Possible extensions to the project
----------------------------------

Remember: You can extend both the parser and the unparser.

Remember: While I am talking about extensions in terms of difficulty,
you are judged as much by the *utility* of the code.

### Comparatively Easy

* Support whitespace in input.
* Error messages
    * Useful/helpful
    * Indicate precisely where the error is
        * Line/column
* Pretty printer

### Moderate

* Pictorial error reporting
* Interactive error reporting
* Parse JSON into actual Java objects that match certain classes
     {"class":"Rational","numerator":1,"denominator":2} =>
     new Rational(1,2)
* Interactive object builder.
* Extend JSON.
* Support for unicode.  "\u1231"

### Difficult

* Output *any* object as JSON code.
* Parse JSON into actual Java objects that match the class.
     {"class":"Rational","numerator":1,"denominator":2} =>
     new Rational(1,2)
* Interactive object builder with audio GUI.

More notes on submitted work
----------------------------

* See document.

Planning presentations
----------------------

* Monday.
* Email to csstudents goes out today.  They get $10 for showing up.
* Three minutes (no more than three slides)
* Send me no more than slides by Sunday at 8pm.  One slide must have your names.
* Handouts optional.
* Prizes!
    * Gift cards!
    * Extra credit!
    * Maybe fruit snax.

Implementing heaps
------------------

* How do we know where the next element goes without looking through the tree
  or doing fancy math?
    * Similarly: How do we find the element to shove at the top when removing
* Basically: Finding the first space at the last level or the last element at
  the last level.
* Two ideas: Binary search trees (divide and conquer data structure) and
  hash tables (key/value and hashing; use an array for efficiency)
* Lets put the heap in an array using left-to-right, breadth-first, top-down
  order
* Shoving into an array.
* How do we find parent, left, and right

Heapsort
--------