COP3503 Computer Science 2
Dr. Andrew Steinberg
Summer 2022
Programming Assignment 3
Secret Messages
Due: 7/22/2022 at 11:59pm
Objective: Students will apply concepts of dynamic programming and the LCS problem.
Assignment Description: Your friend has intercepted a message that is riddled with random
characters. Your friend tries really hard to decipher the message (“qwadhyuit
ejghfhgkllqwrto”),
ut couldn’t. A couple of minutes later your friend receives another message
(“mpoihselyzmxcvldfiuoydmnbv”) riddled with random characters. Something interesting your
friend noticed is that it seems to have the same number of characters. Your friend tells you about
this and you are curious too. You have just listened to a lecture by Dr. Steinberg about finding
longest common sequences and immediately practice on this long message to study for giggles.
After completing by hand the steps of finding the longest common sequence, you get an actual
word (“hello”) as the longest common sequence and realize the secret of this message is through
the longest common subsequence. The next day you tell your friend what you discovered.
Coincidentally your friend receives another two message with the same length of characters.
However, this one is a long sequence and can be time consuming to do by hand. In this
assignment you are going to reveal the secret message. In this assignment, you have intercepted
the document and are going to decipher the message. In order to do this, you will need to apply
the Longest Common Subsequence Algorithm discussed in class. You must apply the dynamic
programming solution. Using another variation will result in losing points.
For this assignment, you must follow these requirements.
1. Create a class called LCS. In this class, you will implement the dynamic programming
algorithm.
2. The class constructor for LCS takes two string objects.
3. In the runner file, you will notice the method “lcsDynamicSol” is invoked. This is the
method that will invoke the dynamic programming solution. Make sure the method name
matches as the runner file in your implementation! Changing names will cause the runner
file not to run or even compile which will result in a low score on the assignment!
4. In the runner file, you will notice the method “getLCS” is invoked. This is the method
that will access the subsequence computed by the dynamic programming solution. This is
the Print-LCS algorithm we discussed in class. Make sure the method name matches as
the runner file in your implementation! Changing names will cause the runner file not to
un or even compile which will result in a low score on the assignment!
5. Make all methods public and class attribute private. It’s good practice!
6. You may create additional helper methods and attributes if needed as long as they are
implemented and called in your solution file and NOT called from the runner file. Adding
extra methods to call in the runner file will not match to what the graders will use
evaluate your code. This will result in a low score with no change to be applied!
COP3503 Computer Science 2
Dr. Andrew Steinberg
Summer 2022
7. Your code must run within 2 seconds on Eustis. If it runs longer than 2 seconds, an
automatic score of 0 will be given for the assignment overall.
A runner file (LCSRunner.java) has been provided for you to show you how the methods are
called along with 4 test cases. The text file is also provided for you that you will need to decipher
using the LCS algorithm. The text file itself must be in the same directory as the runner file. The
number of characters to be read from the file on each line will have no more than 1000
characters.
What to submit: Submit a file called LCS.java to webcourses. You are not required to submit
the runner file as that will be provided for the graders to test your code. Please make sure the
unner file provided works for your code. Any name changes may cause your program not to
work when graded, which will result in a lower score on the assignment and would not be
changed.
Important Note for running Eustis: Many of you are probably using IDEs like Netbeans and
Eclipse to build your Java Solutions. Please note that some of these IDEs will automatically
place your Java file in some sort of package. Please make sure your Java file is not defined in
some package as this can result package private e
ors. Any such e
or that occurs during the
grading will not be fixed and points will be deducted as such in accordance with the respective
categories in the ru
ic. Also, DO NOT create a main method in your solution file!! This will
esult in your code not running properly with the runner file which will result in points being
deducted from the respective categories.
asdmfghsjklmasdafghrjklvasdeffglhjkisaasdfggzxcvbn
vcxzecvn
xfanbvctnbvmspoiuytrhtyuiopoytrewewrwyuiitertitrweoqwertwuiaotpchuotnoooduirsynueypoiuluytrusqwertry
m
tksxbxmqrtyaryyyuuuvpopoelizzxxzqsagrdeatzaqshqowtowpatcuhondxzisnoieyyuiplvbnmufghsdfgxzcmnbvcxzzaplmnjizxcidfghpovgxdzhaapimikgjhkjkokabzamzzzaavfgmxxmbvbx
Beginning Test Cases...
****************************************
Starting with a simple test case...
Test Case 1 Passed!
****************************************
Starting with another simple test case...
Test Case 2 Passed!
The message is...
test
****************************************
****************************************
Starting with even another simple test case...
Test Case 3 Passed!
The message is...
hello
****************************************
Now time for the big test case...
Scanning the file...
Scanning the file complete
Test Case 4 Passed!
The message is...
msmarvelisagreatshowtowatchondisneyplus
****************************************
Yay! All test cases passed!