Assignment 6 - Hash Tables
CSC 354 Given: November 13, 2001
Value: 20 points Due: November 20, 2001
This is a pencil-and-paper assignment.
Objective: understand
·separate chaining and open addressing strategies
·collision resolution for open addressing by linear probing, quadratic probing, and
double hashing
Format
The assignment follows the pattern from class. Given a set of keys to be inserted into a
hash table, your task is to create a hash table first by separate chaining, then by open
addressing. For open addressing:
do the hashing 3 separate times, once with each of the following collision resolution
policies: linear probing, quadratic probing, and double hashing.
if a collision occurs, show the calculations you used to get the probe sequence, as
done in class. IF any mistakes occur, we can view the calculations to find the source
of the mistake.
You can choose the format most comfortable for you. Tables similar to those used in
class are given below. You can compute the appropriate hash values and add them, in
pencil, on the sheets below, or electronically in the Word document (f:\data\turk\csc354\
c354asn6-f01.doc). Alternatively, you can use a spreadsheet to display the hash tables.
Please double check that you are using the given key and in the correct order. You
will lose credit for using an incorrect key and/or order.
Exercise 1 - Separate Chaining
Assume:
·tablesize m = 5
·h(key) = key mod m, which is equivalent to: key % m so slot numbers are 0..4
·insertion is to the front of a list
Keys to be inserted are:
150, 60, 131, 260, 77, 187, 73, 354, 112, 17, 249, 148, 94
Exercise 2 - Open Addressing
Assume:
·tablesize m = 17
·h(key) = key mod m, which is equivalent to: key % m so slot numbers are 0..16
·for double hashing, r = 11, so h2 = 1 + (key mod r)
Keys to be inserted are:
150, 60, 131, 260, 77, 187, 73, 354, 112, 17, 249, 148, 94
CSC 354 1 Fall 2001
