1 TaskDescription
You are asked to use C++ toimplement

• Hash table with linearprobing

2 SubmissionGuideline
You must follow this guideline! Your submission will be marked automatically. Failure to follow this guideline will result in 0.

Your submission should contain exactly one file: main.cpp

You do not need to submit adesign.

Youareaskedtoimplementaveryspecifichashtable.Thekeysarelower-caseEnglishwords(e.g.,apple, pear). The length of a key is at most 10. The hash function is “simply using the last character”. That is, thehashvalueofappleshouldbee,andthehashvalueofpearshouldber.Your hashtablecontainsexactly 26 slots (hash value a to hash value z). The total number of English words/keys you need to deal with is at most 26, so the table is never toosmall.

A table slot has three different statuses: “never used”, “tombstone”, and “occupied”. Table starts with  26 “never used”slots.

Searching works as follows: given a key, take its last character as the  hash  value.  First  try  the  corre- sponding table slot,  if the objective key is there,  then you have found it.  If the corresponding slot is never       used, terminate because we are certain that the objective is not in the table.  If the slot is occupied but it’s not the objective, or the slot is a “tombstone”, then we  move on to the next slot (may need to wrap around       the table if the current slot is the last one). We keep trying until we either find the key or are certain that thekeydoesnotexistinthetable.

Insertion works as follows: First perform searching to  ensure that the  key  does  not  exist.  If it already  exists,  then do nothing.  If it does not,  take the last character of a key as the hash value.  If the corresponding    table slot is not occupied (either “never used” or “tombstone”), put the key there (the slot is now occupied).   If the corresponding slot is already occupied, try the  next  slot.  Repeat  trying  until  you  find  an  unoccupied slot.

Deletion works as follows: given a key, use the searching process to locate its slot. (If the key is not in the table, then do nothing.) Once you find the key, change the slot status to “tombstone”.



You should start your program by initializing an empty hash table. Your program takes one line as input. The input line contains n “modification moves” separated by spaces (1 n 26). The available modification moves are

AWord (Character A followed by a lower-case English word of length at most 10): Aapple means insert key apple into the hash table. If apple is already in the table, do nothing.

DWord (Character D followed by a lower-case English word of length at most 10): Dapple means delete key apple from the hash table. If apple is not in the tree, do nothing.



At the end, you need to go through the slots from a to z, and output all the keys separated by space. You don’t need to worry about invalid inputs.

Sample input 1: Aaaa Accc Abbb Sample output 1: aaa bbb ccc Sample input 2: Abba Aaaa Acca Sample output 2: bba aaa cca Sample input 3: Abba Aaaa Acca Daaa Sample output 3: bba cca


3 Marking
Marking will be done automatically. There are 100 test cases.


4 SVN Instructions
First of all, you need to create a directory under version control:

svn mkdir –parents -m "Creating ADSA project 3 folder" https://version-control.adelaide.edu.au/svn/aXXXXXXX/2018/s2/adsa/project3/

aXXXXXXX should be your student ID. The directory path needs to be exactly “2018/s2/adsa/projectK”, where “K” is the project number. To check out a working copy, type

svn checkout https://version-control.adelaide.edu.au/svn/aXXXXXXX/2018/s2/adsa/project3/ adsa-18-s2-project3/ cd adsa-18-s2-project3

svn add main.cpp

Commit the files to SVN:

svn commit -m "Adding ADSA project 3 main.cpp"

SVN helps keeping track of file changes (over different commits). You should commit your work early and often.


5 Websubmission
You are asked to submit via the web interface https://cs.adelaide.edu.au/services/websubmission/. The submission steps should be self-explanatory.  Simply choose the correct semester,  course,  and project.   The websubmission system will automatically fetch the latest version of your work from your SVN repository     (you may also choose to submit  older  versions).  Once  your  work  is  submitted,  the  system  will  launch  a  script checking the format of your submission.  Click “View Feedback” to view the results. Your mark will be calculated offline after the deadline. You are welcome to resubmit for as many times as you wish (before        the deadline).

We will compile your code using g++ -o main.out -std=c++11 -O2 -Wall main.cpp. It is your re- sponsibility to ensure that your code compiles on the university system.1




1g++ has too many versions, so being able to compile on your laptop does not guarantee that it compiles on the university

system. You are encouraged to debug your code on a lab computer (or use SSH).