Comp 271-400 Week 4

Lewis Tower 410, 4:15-8:15    Nov 13

Welcome

Readings:

    Bailey chapter 6, on sorting
    Bailey chapter 9, on lists (and, in particular, linked lists)
    Bailey chapter 15.4.2: (chained) hashing

    Morin chapter 1, sections 1.1 and 1.2
        One slight peculiarity of Morin is that he refers to the array-based List implementation of chapter 2 as an ArrayStack.

Primary text: Bailey, online, and maybe Morin, also online.

Information about MSDNAA is in the Intro to C++ section



There's an algorithmic reason why quicksort's speed is affected by whether the data is already sorted: if we pick data[left] as the pivot in a sorted array, we'll partition into an empty left half and a right half of size N-1.

But why should mergesort be faster if the data is already sorted? The algorithm executes exactly the same steps!
Demo: pldsorting/SortTester.java

Radix Sort

    133    312    121    213    122    211    321    132   223    332

Naive approach: bucketize on the first digit, then sort the buckets recursively.
1337 approach: bucketize on the last digit, concatenate, bucketize on second-to-last digit, concatenate, bucketize on the first digit (third-to-last digit)


Trees

binary trees
insertion and search

Lab 4: tree-based dictionary
    insertion code

Recursion

Recursion starts at Bailey page 94
See recursion.html and recursion1ij.zip.


Trees

traversal
tree-based dictionaries