Oct 5, Mathematica lecture notes

 * Questions / discussion of work status

 * go over Quicksort algorithm : 
  (1) Work on part of the list, from left .. right (both indeces).
  (2) Pick a pivot, left <= pivot <= right
  (3) Re-order the list so that the pivot is in the correct spot :
      (a) move the pivot to the far right
      (b) store a "wherePivotGoes" index at the far left
      (c) loop through the list looking for things smaller than the pivot.
          For each smaller than the pivot,
          * put it at "wherePivotGoes",
          * increment "wherePivotGoes"
      (d) finally, swap the pivot to its correct place
  (4) repeat recursively on the left and right parts of the list
       
 * See code/quick_sort.nb for some Mathematica code, 
   including an animation (!)

 * Recursion :

   fractals
   natural language
   trees (real ones and searches)

 * Keeping a list ordered by adding elements one by one
   to a binary tree

 * looping over a tree
   * depth first
   * breadth first