We may make minor changes to the spec to address/clarify some outstanding issues. These may require minimal changes in your design/code, if at all. Students are strongly encouraged to check the change log regularly.
Assignment
COMP9024 23T2
Prof Michael Thielscher
Change Log
Version 1: Released on 7 July 2023
Objectives
The assignment aims to give you more independent, self-directed practice with
advanced data structures, especially graphs graph algorithms
asymptotic runtime analysis
Marks 3 marks for stage 1 (correctness) 5 marks for stage 2 (correctness) 2 marks for stage 3 (correctness)
1 mark for complexity analysis 1 mark for style ———————
Total: 12 marks
Due 5:00:00pm on Monday 31 July (week 10) Late 5% penalty per day late
(e.g. if you are 25 hours late, your mark will be reduced by 10%)
The objective is to write a program tripView.c that generates an optimal trip on (a part of) Sydney’s railway network based on user preferences. Input
Railway stations
The first input to your program consists of an integer n > 0, indicating the number of railway stations on the network, followed by n*2 lines of the form:
where the first line is the name of a station and the second line denotes the time – in minutes – it takes to transfer to a different train at that station. Here is an example:
prompt$ ./tripView Size of network: 3 HarrisPark
NorthSydney
You may assume that:
The input is syntactically correct.
The maximum length (strlen()) of the name of a railway station is 16 and will not use any spaces. The transfer time will be a positive integer.
No name will be input more than once.
To read a single line with a station name you should use:
scanf(“%s”, name);
where name is a string, i.e. an array of chars.
Timetables
The next input to your program is an integer m > 0, indicating the number of trains on any day, followed by m timetables. Each timetable starts with the number s > 1 of stops followed by s*2 lines of the form:
meaning that you can get on or off the train at that station at the given time (hh – hour, mm – minute). Here is an example:
Number of timetables: 2 Number of stops: 3 HarrisPark
NorthSydney
Number of stops: 2 TownHall
NorthSydney
You may assume that:
The input is syntactically correct.
All times are given as 4 digits and are valid, ranging from 0000 to 2359.
Only train stations that have been input earlier as part of the network will be used. The stops are input in the correct temporal order.
All trains reach their final stop before midnight.
The final input to your program are user queries:
From: HarrisPark
To: NorthSydney
Arrive at or before: 1200
As before, you may assume that the input is correct: Two different valid railway stations followed by a valid time in the form of 4 digits. Your program should terminate when the user enters “done” when prompted with From:
From: done Bye prompt$
Stage 1 (3 marks)
Stage 1 requires you to generate a suitable data structure from the input.
Test cases for this stage will only use queries FromStation, ToStation, ArrivalTime such that:
there exists one, and only one, train that travels from FromStation to ToStation ; this train arrives on, or before, the given ArrivalTime ; and
this train is the desired output for the query.
Therefore, at this stage all you need to do is find and output the connection between the two train stations, including all the stops along the way and the arrival/departure times. Here is an example to demonstrate the expected behaviour of your program for a stage 1 test:
prompt$ ./tripView Size of network: 7 Ashfield
HarrisPark
MilsonsPoint
NorthSydney
Number of timetables: 2 Number of stops: 5 HarrisPark
NorthSydney
Number of stops: 4 Redfern
MilsonsPoint
From: Central
To: MilsonsPoint
Arrive at or before: 1600
1406 Central
1410 TownHall
1430 MilsonsPoint
From: Ashfield
To: NorthSydney
Arrive at or before: 1040
0955 Ashfield
1006 Redfern
1020 TownHall
1035 NorthSydney
From: done Bye prompt$
Stage 2 (5 marks)
For the next stage, your program should find and output a connection from FromStation to ToStation that:
may involve one or more train changes;
arrives at ToStation no later than ArrivalTime ; and leaves as late as possible.
Note that you can get onto a different train at any station, but it is necessary to take into account the time it takes to change trains at that station.
In all test scenarios for this stage there will be at most one connection that satisfies all requirements.
Here is an example to demonstrate the expected behaviour of your program for stage 2:
prompt$ ./tripView Size of network: 6 Ashfield
HarrisPark
NorthSydney
Number of timetables: 2 Number of stops: 5 HarrisPark
NorthSydney
Number of stops: 3 HarrisPark
From: HarrisPark
To: NorthSydney
Arrive at or before: 1040
0950 HarrisPark
1010 Central
1017 TownHall
Change at TownHall
1020 TownHall
1035 NorthSydney
From: done Bye prompt$
If there is no connection that satisfies the requirements, then the output should be: No connection.
From: HarrisPark To: TownHall Arrive by: 1015
No connection.
Stage 3 (2 marks)
For the final stage, if there are multiple possible connections with the same latest departure time, your program should take into account the additional user preference that: among all the connections with the latest possible departure time, choose the one with the shortest overall travel time.
You may assume that there will never be more than one connection with the latest possible departure time and the shortest overall travel time. Note also that travel time includes the time it takes to change trains and the waiting time if applicable. Here is an example to demonstrate the expected behaviour of your program for stage 3:
prompt$ ./tripView Size of network: 3 HarrisPark
NorthSydney
Number of timetables: 2 Number of stops: 3 HarrisPark
NorthSydney
Number of stops: 2 TownHall
NorthSydney
From: HarrisPark
To: NorthSydney
Arrive at or before: 1040
0945 HarrisPark
1020 TownHall
Change at TownHall
1024 TownHall
1033 NorthSydney
From: done Bye prompt$
Complexity Analysis (1 mark)
You should include a time complexity analysis for the asymptotic worst-case running time of your program, in Big-Oh notation, depending on the size of the input:
1. the size of the network, n
2. the number of timetables, m
3. the maximum number of stops on any one timetable, s.
If you find any of the following ADTs from the lectures useful, then you can, and indeed are encouraged to, use them with your program:
linked list ADT : list.h, list.c
stack ADT : stack.h, stack.c
queue ADT : queue.h, queue.c
priority queue ADT : PQueue.h, PQueue.c graph ADT : Graph.h, Graph.c
weighted graph ADT : WGraph.h, WGraph.c
You are free to modify any of the six ADTs for the purpose of the assignment (but without changing the file names). If your program is using one or more of these ADTs, you should submit both the header and implementation file, even if you have not changed them. Your main program file tripView.c should start with a comment: /* … */ that contains the time complexity of your program in Big-Oh notation, together with a short explanation.
We have created a script that can automatically test your program. To run this test you can execute the dryrun program that corresponds to this assignment. It expects to find, in the current directory, the program tripView.c and any of the admissible ADTs (Graph,WGraph,stack,queue,PQueue,list) that your program is using, even if you use them unchanged. You can use dryrun as follows:
prompt$ 9024 dryrun tripView
Please note: Passing dryrun does not guarantee that your program is correct. You should thoroughly test your program with your own test cases.
For this project you will need to submit a file named tripView.c and, optionally, any of the ADTs named Graph,WGraph,stack,queue,PQueue,list that your program is using, even if you have not changed them. You can either submit through WebCMS3 or use a command line. For example, if your program uses the Graph ADT and the queue ADT, then you should submit:
prompt$ give cs9024 assn tripView.c Graph.h Graph.c queue.h queue.c Do not forget to add the time complexity to your main source code file tripView.c.
You can submit as many times as you like — later submissions will overwrite earlier ones. You can check that your submission has been received on WebCMS3 or by using the following command:
prompt$ 9024 classrun -check assn Marking
This project will be marked on functionality in the first instance, so it is very important that the output of your program be exactly correct as shown in the examples above. Submissions which score very low on the automarking will be looked at by a human and may receive a few marks, provided the code is well- structured and commented.
Programs that generate compilation errors will receive a very low mark, no matter what other virtues they may have. In general, a program that attempts a substantial part of the job and does that part correctly will receive more marks than one attempting to do the entire job but with many errors. Style considerations include:
Readability
Structured programming Good commenting
Plagiarism
Group submissions will not be allowed. Your programs must be entirely your own work. Plagiarism detection software will be used to compare all submissions pairwise (including submissions for similar assessments in previous years, if applicable) and serious penalties will be applied, including an entry on UNSW’s plagiarism register.
You are not permitted to use code generated with the help of automatic tools such as GitHub Pilot, ChatGPT, Google Bard.
Do not copy ideas or code from others
Do not use a publicly accessible repository or allow anyone to see your code
Code generated by GitHub Pilot, ChatGPT, Google Bard and similar tools will be treated as plagiarism.
Please refer to the on-line sources to help you understand what plagiarism is and how it is dealt with at UNSW:
Plagiarism and Academic Integrity
UNSW Plagiarism Policy
UNSW Plagiarism Management Procedure
See FAQ for some additional hints.
Finally …
Have fun! Michael
Reproducing, publishing, posting, distributing or translating this assignment is an infringement of copyright and will be referred to UNSW Conduct and Integrity for action.
railway-station
transfer-time
station hhmm
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