Data Structures and Algorithms
COMP9024 20T3
Objectives
Assignment
TripPlanner
The assignment aims to give you more independent, self-directed practice with
• advanced data structures, especially graphs
• graph algorithms
• asymptotic runtime analysis
• understanding how to use graphs to solve problems in real life.
Aim
Your task is to write a program TripPlaner.c for finding an optimal bus connection that takes into account a given arrival time and user preferences.
To implement the TripPlaner you will need to implement a simple bus network. For that you will use a digraph to represent a bus network and implement several functions for the bus network to enable it usage.
Admin
Marks
3 marks for stage 1 (correctness) 5 marks for stage 2 (correctness) 2 marks for stage 3 (correctness) 1 marks for complexity analysis 1 mark for style
——————— Total: 12 marks
Due
12:00 noon on Monday 23 November
Late
2 marks (16.67%) off the ceiling per day late
(e.g. if you are 25 hours late, your maximum possible mark is 8)
Data Structures and Algorithms COMP9024 20T3
The TripPlaner
The bus network will consists of a set of bus stops and the bus schedule. • Each bus stop has a unique name that consists of one word, such as
Parramatta.
• Each bus has a schedule, given in “hhmm” meaning that passengers can get on or off the bus at that time (hh – hour, mm – minute) at particular bus stop.
Input
Bus Stop names
Your program should start by prompting the user to input a positive number n followed by n lines, each containing the name of a bus stop. An example Is:
You may assume that:
• The input is syntactically correct.
• Bus stop names require no more than 31 characters and will not use
any spaces.
• No bus stop name will be input more than once.
Hint:
To read a single line with a bus stop name you may use “scanf”.
Buses
Next, your program should ask the user for the number m of busses running during a day, followed by m schedules.
Each schedule requires the number of stops, k≥2, followed by k*2 lines of the form:
Data Structures and Algorithms COMP9024 20T3
If you enter: 2 busses, for each bus you need to provide the schedule, for example:
You may assume that:
• The input is syntactically correct: 4 digits followed by the name of a bus
stop on a new line.
• All times are valid and range from 0000 to 2359.
• Stops are input in the right (temporal) order.
• There are no overnight busses: Each bus will reach its final stop before
midnight.
• Only valid bus stop names that have been input before will be used.
Queries
After reading the network, your program should enable the user to search for a connection, by prompting the user to enter: From,To and desired arrival time, ArriveBy. For example :
When you finish using the program, you should type “done”. Then your program should terminate, for example:
Data Structures and Algorithms COMP9024 20T3
Stage 1 (3 marks)
For stage 1, you should demonstrate that you can read the input and generate a suitable data structure.
For this stage, all test cases will only use queries (From, To, ArriveBy) for which
• there is only one bus between From and To ; and
• this bus is guaranteed to arrive on, or before, the requested time,
ArriveBy .
Hence, all you need to do for this stage is find and output this bus connection, including all stops along the way and the arrival/departure times. Here is an example to show the desired behaviour of your program for a stage 1 test
Data Structures and Algorithms COMP9024 20T3
Stage 2 (5 marks)
For stage 2, you should extend your program for stage 1 such that it always finds, and outputs, a connection between From and To that
• arrives on, or before, the requested time ArriveBy ; and
• departs as late as possible.
You should assume that:
• Changing busses takes no time: Passengers arriving at a bus stop can
get onto any other bus that leaves that stop at the same time or later.
• In all test scenarios there will be at most one connection that satisfies
all requirements.
If there is no connection, the output should be:
Here is an example to show the desired behaviour and output of your program for a stage 2 test:
Data Structures and Algorithms COMP9024 20T3
Stage 3 (2 marks)
For stage 3, you should extend your program for stage 2 such that:
If there are two or more connections with the same latest departure time, choose the one with the earliest arrival time.
Here is an example to show the desired behaviour and output of your program for a stage 3 test:
Data Structures and Algorithms COMP9024 20T3
Complexity Analysis (1 mark)
Your program should include a time complexity analysis for the worst-case asymptotic running time of your program, in Big-Oh notation, depending on the size of the input:
1. the number of bus stops, n
2. the number of busses, m
3. the maximum number k of stops on a bus line.
Hints
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 :
• queue ADT :
• graph ADT :
• weighted graph ADT : WGraph.h, WGraph.c
stack.h, stack.c queue.h, queue.c
Graph.h, Graph.c
Data Structures and Algorithms COMP9024 20T3
You are free to modify any of the five 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 TripPlaner.c should start with a comment: /* … */ that contains the time complexity of your program in Big-Oh notation, together with a short explanation.
Testing
The dryrun and additional test cases will be available soon, please test your program with your own test cases until then.
Submit
For this project you will need to submit a file named TripPlaner.c and, optionally, any of the ADTs named Graph,WGraph,stack,queue,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:
Do not forget to add the time complexity to your main source code file
TripPlaner.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:
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.
Data Structures and Algorithms COMP9024 20T3
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 program must be entirely your own work. Plagiarism detection software will be used to compare all submissions pairwise (including submissions for similar projects in previous years, if applicable) and serious penalties will be applied, particularly in the case of repeat offences.
• Do not copy ideas or code from others
• Do not use a publicly accessible repository or allow anyone to see
your code, not even after the deadline
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 Statement • UNSW Plagiarism Procedure