Data Structures and Algorithms in Java[1].pdf - Fulvio Frisone

3.6 Exercises
For source code and help with exercises, please visit
java.datastructures.net.
Reinforcement
R-3.1
The add and remove methods of Code Fragments 3.3 and 3.4 do not keep
track of the number,n, of non-null entries in the array, a. Instead, the unused
cells point to the null object. Show how to change these methods so that they
keep track of the actual size of a in an instance variable n.
R-3.2
Describe a way to use recursion to add all the elements in a n × n (two
dimensional) array of integers.
R-3.3
Explain how to modify the Caesar cipher program (Code Fragment 3.9) so that
it performs ROT 13 encryption and decryption, which uses 13 as the alphabet
shift amount. How can you further simplify the code so that the body of the
decrypt method is only a single line?
R-3.4
Explain the changes that would have be made to the program of Code Fragment
3.9 so that it could perform the Caesar cipher for messages that are written in an
alphabet-based language other than English, such as Greek, Russian, or Hebrew.
R-3.5
What is the exception that is thrown when advance or remove is called on an
empty list, from Code Fragment 3.25? Explain how to modify these methods so
that they give a more instructive exception name for this condition.
R-3.6
Give a recursive definition of a singly linked list.
R-3.7
Describe a method for inserting an element at the beginning of a singly linked
list. Assume that the list does not have a sentinel header node, and instead uses
a variable head to reference the first node in the list.
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