Assignment 2: Linked Lists


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In this assignment, you will be reading in words from a pronunciation dictionary to figure out
which words rhyme with each other.
To do this, you will be implementing MyLinkedList and MySortedLinkedList. Besides the lectures
in class, you can read much more about the code details of how linked lists work in the book on
pages 249-268.
You’ll be implementing the following:
● A linked list in MyLinkedList that implements interface ListInterface. You’ll be using
MyLinkedList in two different ways, to store a list of RhymeGroupWords and to store a
list of Strings within each RhymeGroupWords object. More on this below.
● Code in the main method of RhymingDict that takes lines that have been read from a
rhyming dictionary and stores them in the lists.
● A subclass of MyLinkedList called MySortedLinkedList, that has a method for adding
items into the list in sorted order.
● Code in the main method of RhymingDict that takes pairs of words specified on the
command line and outputs whether they rhyme or not.
A LinkedList is useful for storing information when you don’t know how many items you need to
store. In this lab, we will be iterating through a rhyming dictionary and storing words together
according to their rhyming group, which is the most heavily emphasized part of their
In the directory of starter code for the assignment, you’ll see a subdirectory called cmudict.
Inside is a file called cmudict-short.dict. Opening this, you’ll see lines like:
dignitary D IH1 G N AH0 T EH2 R IY0
necessitate N AH0 S EH1 S AH0 T EY2 T
undue AH0 N D UW1
moderated M AA1 D ER0 EY2 T IH0 D
The letters after the words represent the phonemes (units of sound) you speak when you
pronounce the word. The phonemes that have numbers after them (0, 1 or 2) are the
emphasized phonemes, with phonemes marked with 2 having the most emphasis (say the
words out loud to yourself to try this out). Two words rhyme if the share the same subset of
phonemes after the most emphasized phoneme. For example:
moderated M AA1 D ER0 EY2 T IH0 D
anticipated AE0 N T IH1 S AH0 P EY2 T IH0 D
both rhyme, and they both share EY2 T IH0 D starting with the most emphasized phoneme.
The EY2 T IH0 D is called the rhyming group for these two words. You’ll be storing rhyming
groups in a linked list of RhymeGroupWords, a class you’ve been provided in the starter code.
Each RhymeGroupWords object stores a string with the rhyme group EY2 T IH0 D and a list of
words that share the rhyme group (a variable of type ListInterface). So you’ll be using linked
lists in two different ways: to store a list of RhymeGroupWords, and, within each
RhymeGroupWords object, to store a list of words.
The file is provided for you. It already has the following:
● A method getRhymeGroup(String line), which returns the rhyme group for a line
from the dictionary. For example getRhymeGroup(“moderated M AA1 D ER0 EY2 T
IH0 D”) returns “EY2 T IH0 D”.
● A method getWord(String line), which returns the word for a line from the dictionary.
For example, getWord(“moderated M AA1 D ER0 EY2 T IH0 D”) returns
● A method loadDictionary(), which returns a String[] of all the lines from the
pronunciation dictionary.
The tasks you have to do is marked with the comment TODO in the main method of
RhymingDict. These tasks are:
1. Use your implementation of MyLinkedList to create a linked list of RhymeGroupWords, one
for each unique rhyme group you encounter (there are 8 unique rhyme groups in
cmudict-short.dict). Within each RhymeGroupWords you’ll store a MySortedLinkedList of
words that share that rhyme group.
2. Iterate through pairs of arguments to RhymingDict and use your linked list to determine if the
pair of words rhyme. For example, with the command:
java RhymingDict crumbling mumbling collections abbreviated vegetate mutate
the output would be:
crumbling and mumbling rhyme
collections and abbreviated don’t rhyme
mutate is not in the dictionary
In the case of the last pair of words, “vegetate” and “mutate”, since the word “mutate”
doesn’t appear in cmudict-short.dict, it reports that and ignores “vegetate”. If an odd
number of words is passed on the command line, it ignores the last word (since it’s not part of a
Do not use built-in Java data structures (like ArrayList or LinkedList) in this file
The points for this assignment are allocated as follows:
● 35 points for implementing MyLinkedList. Even if you don’t get the rest of the
assignment working, you can still earn points for a correct implementation of
MyLinkedList (we will be running test code to test it).
● 30 points for correctly storing the rhyme groups and words in linked lists using
MyLinkedList for both the RhymeGroupWords list and the word lists in each
RhymeGroupWords. In this case the words won’t appear in sorted order in the list.
● 20 points for implementing and using MySortedLinkedList to store the word lists. Now
the words within each rhyme group will appear in sorted order.
● 15 points for writing the code that processes arguments to determine if pairs of
arguments rhyme.
Our recommendation is that you do the parts of the assignment in this order. There is some
commented out test code in main for testing MyLinkedList without having to store the
pronunciation dictionary in it. Feel free to edit this code to do more tests, but make sure to
comment it out before you turn in your assignment. Once you have MyLinkedList working with
your tests, then use it to store the data from the dictionary. Test if you’re getting 8 rhyme
groups. The output below shows what the rhyme groups will look like with the words in sorted
order, though at this point your words won’t be sorted yet. Then implement
MySortedLinkedList and use it for storing the word lists. Now your rhyme groups should print
out with the words in sorted order. Finally, write the code that searches through the lists to see if
a pair of words rhyme.
The following files are provide for you:
● – described above
● – specifies the methods you need to implement in MyLinkedList
● – an empty class file that implements ListInterface
● – an empty class file that extends MyLinkedList.
Comments in the file specify what the one method and one method override should be
● – a class for storing a rhyme group and the list of words that
share that rhyme group (described above)
● – an exception to throw when a list index is
out of bounds in MyLinkedList.
Turning the code in
● Create a directory with the following name: _assignment2 where
you replace with your actual student ID. For example, if your
student ID is 1234567, then the directory name is 1234567_assignment1.
● Put a copy of your edited, and files in the directory.
● Compress the folder using zip. Zip is a compression utility available on mac, linux
and windows that can compress a directory into a single file. This should result in
a file named (with replaced with
your real ID of course).
● Upload the zip file through the page for Assignment 2 in canvas
Example Arguments and Output
Below I show the output for one example command. You should of course test your code with
different words as arguments as well.
For the example command:
java RhymingDict crumbling mumbling collections abbreviated vegetate mutate
the output will be as follows. First it prints out the 8 rhyme groups and all their words, then which
pairs of words on the command line rhyme. The words in this case are in alphabetical order
because they were stored using MySortedLinkedList.
EH2 R IY0: (adversary, apothecary, arbitrary, banbury, blackberry,
canterbury, cemetery, commentary, confectionery, constabulary, culinary,
customary, depositary, dictionary, dietary, dignitary, disciplinary,
discretionary, dromedary, dubarry, dysentery, emissary, estuary, feb,
february, functionary, gooseberry, hereditary, honorary, itinerary,
january, judiciary, legendary, literary, luminary, mercenary, military,
missionary, momentary, monastery, monetary, mortuary, mulberry, necessary,
obituary, ordinary, pecuniary, primary, proprietary, reactionary, rosemary,
salutary, sanitary, savagery, secondary, secretary, sedentary, seminary,
solitary, stationary, stationery, statuary, strawberry, temporary,
tributary, unnecessary, unsanitary, veterinary, visionary, vocabulary,
EY2 T: (abdicate, abrogate, accelerate, accommodate, accumulate, aggravate,
alienate, alleviate, amalgamate, ameliorate, amputate, annihilate,
anticipate, arbitrate, arrogate, aspirate, assassinate, assimilate,
captivate, carbonate, checkmate, circulate, commemorate, commiserate,
communicate, compensate, complicate, concentrate, congregate, consecrate,
consolidate, contaminate, contemplate, cooperate, corroborate, culminate,
cultivate, decapitate, decorate, dedicate, delegate, delineate,
demonstrate, denominate, depopulate, depreciate, designate, deteriorate,
determinate, devastate, deviate, discriminate, disintegrate, disseminate,
dissipate, educate, elevate, elucidate, emanate, emancipate, emigrate,
enumerate, evacuate, exasperate, excavate, expiate, extenuate, exterminate,
extirpate, extricate, facilitate, fascinate, felicitate, flagellate,
fluctuate, generate, gravitate, hesitate, humiliate, hundredweight,
illustrate, imitate, immolate, implicate, inculcate, indicate, inmate,
instigate, isolate, legislate, locate, lubricate, magistrate, mandate,
mediate, meditate, migrate, militate, mitigate, mutilate, narrate,
navigate, necessitate, negotiate, nitrate, obliterate, obviate, officiate,
operate, originate, overstate, paperweight, participate, penetrate,
perforate, permeate, perpetuate, playmate, pontificate, precipitate,
predominate, premeditate, primate, probate, procrastinate, profligate,
propagate, punctuate, recreate, recuperate, regenerate, regulate,
reiterate, repudiate, retaliate, rotate, ruminate, saturate, schoolmate,
segregate, separate, shipmate, situate, stagnate, stimulate, stipulate,
subjugate, sulphate, terminate, underestimate, undulate, vacillate,
vegetate, venerate, vertebrate, vitiate)
UW1: (accrue, adieu, ado, anew, askew, bamboo, bleu, blew, blue, boo, brew,
canoe, chew, cou, coup, crew, crewe, cue, debut, deux, dew, doo, drew, du,
due, ensue, ewe, few, flew, flue, glue, goo, grew, gu, gue, hew, hoo, hu,
hue, jew, jus, kew, knew, ku, misconstrue, moo, new, nu, ooh, ou, peru,
pew, phew, pooh, pursue, q, qu, que, queue, revue, rue, shampoo, shew,
shoe, shoo, sioux, slew, stew, strew, su, subdue, sue, taboo, threw,
through, to, too, true, two, u, undo, undue, untrue, view, vous, vue, whew,
who, withdrew, woo, you, zoo)
EY2 T IH0 D: (abbreviated, abdicated, abrogated, accelerated, accentuated,
accommodated, accumulated, adulterated, advocated, aggravated, aggregated,
agitated, alienated, alleviated, amalgamated, ameliorated, amputated,
animated, annihilated, anticipated, antiquated, appreciated, appropriated,
articulated, asphyxiated, assassinated, assimilated, associated,
attenuated, bifurcated, calculated, capitulated, captivated, castrated,
celebrated, circulated, collaborated, commemorated, communicated,
concentrated, congratulated, congregated, consecrated, contaminated,
contemplated, corroborated, corrugated, cultivated, debilitated, decimated,
degenerated, deliberated, delineated, demonstrated, denominated,
depreciated, designated, deteriorated, devastated, deviated, dilapidated,
discriminated, dissipated, duplicated, educated, elevated, eliminated,
emanated, emancipated, emigrated, emulated, enumerated, enunciated,
eradicated, exasperated, excavated, excoriated, exonerated, exterminated,
facilitated, gravitated, hesitated, humiliated, imitated, implicated,
inaugurated, infiltrated, intimated, inundated, irrigated, manipulated,
migrated, miscalculated, moderated, narrated, navigated, obligated,
obliterated, opinionated, outdated, oxygenated, participated, penetrated,
perforated, permeated, perpetrated, perpetuated, populated, precipitated,
predominated, premeditated, procrastinated, promulgated, propagated,
radiated, reciprocated, recuperated, regenerated, regulated, reiterated,
rejuvenated, relegated, renovated, repudiated, resuscitated, retaliated,
reverberated, ruminated, saturated, segregated, separated, serrated,
simulated, situated, sophisticated, speculated, stimulated, stipulated,
subjugated, subordinated, substantiated, suffocated, syncopated, tabulated,
tolerated, truncated, uneducated, unmitigated, venerated, ventilated)
EH1 N D IH0 NG: (amending, ascending, bending, blending, commending,
defending, depending, descending, ending, extending, lending, mending,
offending, pending, portending, pretending, rending, sending, spending,
suspending, tending, transcending, trending, unending, wending)
AH1 M B AH0 L IH0 NG: (crumbling, grumbling, humbling, mumbling, rumbling,
IY1 Z AH0 N AH0 B L IY0: (reasonably, unreasonably)
EH1 K SH AH0 N Z: (affections, collections, complexions, connexions,
corrections, elections, erections, objections, projections, protections,
reflections, rejections, sections)
crumbling and mumbling rhyme
collections and abbreviated don’t rhyme
mutate is not in the dictionary