COMP9021 Principles of Programming

标签：labyrinth Programming Principles will points connected following txt COMP9021

COMP9021 Principles of Programming

Term 2, 2024

Assignment 2

Worth 13marks and due Week 11 Monday @ 10am

General Matters

1.1 Aim

The purpose of this assignment is to:

Develop your problem-solving skills.
Design and implement the solution to a problem in the form of a medium sized Python program.
Analyse the various features of a labyrinth, represented by a particular coding of its basic elements

into numbers, from the set {0, 1, 2, 3} only, stored in a text file.

Check that the input text file is correct and represents a labyrinth.
Output the labyrinth features nicely.
Use object-oriented programming.

1.2 Marking

This assignment is worth 13 marks distributed as follows:

Your program will be tested against several inputs. For each test, the auto-marking script will let your

program run for 30 seconds. The outputs of your program should be exactly as indicated.

1.3 Due Date and Submission

Your programs will be stored in a file named labyrinth.py. The assignment can be submitted more than

once. The last version just before the due date and time will be marked (unless you submit late in which

case the last late version will be marked).

Assignment 2 is due Week 11 Monday 5 August 2024 @ 10:00am (Sydney time).

Please note that late submission with 5% penalty per day is allowed up to 5 days from the due date, that

is, any late submission after Week 11 Saturday 10 August 2024 @ 10:00am will be discarded.

Please make sure not to change the filename labyrinth.py while submitting by clicking on [Mark] button in

Ed. It is your responsibility to check that your submission did go through properly using Submissions link in

Ed otherwise your mark will be zero for Assignment 2.

1.4 Reminder on Plagiarism Policy

You are permitted, indeed encouraged, to discuss ways to solve the assignment with other people. Such

discussions must be in terms of algorithms, not code. But you must implement the solution on your own.

Submissions are scanned for similarities that occur when students copy and modify other people’s work or

work very closely together on a single implementation. Severe penalties apply.

Description

The representation of the labyrinth is based on a coding with only the four digits 0, 1, 2 and 3 such that:

0 codes points that are connected to neither their right nor their below neighbours:
1 codes points that are connected to their right neighbours but not to their below ones:
2 codes points that are connected to their below neighbours but not to their right ones:
3 codes points that are connected to both their right and below neighbours:

A point that is connected to none of their left, right, above, and below neighbours represents a pillar:

Analysing the labyrinth will also allow to represent:

cul-de-sac:
entry-exit path: 3. Examples

3.1 First Example

The file named labyrinth_1.txt contains the following:

1 0 2 2 1 2 3 0

3 2 2 1 2 0 2 2

3 0 1 1 3 1 0 0

2 0 3 0 0 1 2 0

3 2 2 0 1 2 3 2

1 0 0 1 1 0 0 0

As per the coding above, labyrinth_1.txt will look like the following:

Here is a possible interaction:

3.2 Second Example

The file named labyrinth_2.txt contains the following:

022302120222

222223111032

301322130302

312322232330

001000100000

As per the coding above, labyrinth_2.txt will look like the following:

Here is a possible interaction:3.3 Third Example

The file named labyrinth_3.txt contains the following:

31111111132

21122131202

33023022112

20310213122

31011120202

21230230112

30223031302

03122121212

22203110322

22110311002

11111101110

As per the coding above, labyrinth_3.txt will look like the following:

Here is a possible interaction:

3.4 Fourth Example

The file named labyrinth_4.txt contains the following:

111120

112020

002020

002010

001110

As per the coding above, labyrinth_4.txt will look like the following:

Here is a possible interaction:7

3.5 Fifth Example

The file named labyrinth_5.txt contains the following:

1 1 2

1 12

1 1 0

As per the coding above, labyrinth_5.txt will look like the following:

Here is a possible interaction:3.6 Sixth Example

The file named labyrinth_6.txt contains the following:

0111221210021212201201323330200

1131011210301210323130331302310

3300200323203011010332232320332

2330312230220302032203223112310

1211020213223110101302032332212

1112222331300131013312312223130

1110120222130303102210113130100

0020320223200020113011131202302

3213100301021111202122030110112

1200320130030313001031302312110

0310130300203000312021011212020

3131210323320222322212332031120

2021033213003230103112331130222

1013300313133312220131222100010

1231322020123133221023110302002

3322231133223020311032001102310

2323101332332011010132023031132

2200112102133112231003320012120

2130210032120230313010200102112

2311003320123302322223032120112

0201320233130133202333323012120

1003010311132003122332112221132

2032100103021312110202200332310

3211202310233321202022122021022

1200330103010322222131033003000

1121200200313110310030131100332

0012021023310003332301123031222

0120302110232113312232012023020

2303222021330232031311210131312

0101112200130031003120203121102

2012100113233120321011002012220

0010322001332202013202312122110

0213000131303132112301110130112

1222303101032032301032210302110

1220131300113200003021222120012

1333010013001231321110022323022

3021223221133030131221100102210

2013320130211320203021000311312

0303003010033021320232203222020

2030233001202311110121110133220

1001011011001101100000010100100

8As per the coding above, labyrinth_6.txt will look like the following:

910

Here is a possible interaction:11

Detailed Description

4.1 Input

The input is expected to consist of ydim lines of xdim members of {0, 1, 2, 3}, where x dim and ydim are at least

equal to 2 and at most equal to 31 and 41, respectively, with possibly lines consisting of spaces only that

will be ignored and with possibly spaces anywhere on the lines with digits.

The xth digit n of the yth line, with 0 ≤ x < xdim and 0 ≤ y < ydim, is to be:

associated with a point situated x * 0.5 cm to the right and y * 0.5 cm below an origin,
connected to the point 0.5 cm to its right if n = 1 or n = 3, and
connected to the point 0.5 cm below itself if n = 2 or n = 3.

The last digit on every line with digits (that is, not on blank lines) cannot be equal to 1 or 3, and the digits

on the last line with digits cannot be equal to 2 or 3, which ensures that the input encodes a labyrinth,

that is, a grid of width (xdim - 1) * 0.5 cm and of height (ydim - 1) * 0.5 cm (hence of maximum width 15 cm

and of maximum height 20 cm), with possibly gaps on the sides and inside.

A point not connected to any of its neighbours is thought of as a pillar and a point connected to at least

one of its neighbours is thought of as part of a wall.

We talk about inner point to refer to a point that lies (x + 0.5) * 0.5 cm to the right of and (y + 0.5) * 0.5

cm below the origin with 0 ≤ x < xdim - 1 and 0 ≤ y < ydim - 1.

Practically, the input will be stored in a text file as shown in the six examples above. The program will exit

immediately if the input is not as expected.

4.2 Output

Consider executing from the Python prompt the statement from labyrinth import * followed by the

statement lab = Labyrinth(filename). In case filename does not exist in the working directory, then Python

will raise a FileNotFoundError exception, that does not need to be caught. Assume that filename does

exist (in the working directory). If the input is incorrect in that it does not contain only digits in {0, 1, 2, 3}

besides spaces, or in that it contains either too few or too many nonblank lines, or in that some nonblank

lines contain too many or too few digits, or in that two of its nonblank lines do not contain the same

number of digits, then the effect of executing lab = Labyrinth(filename) should be to generate a

LabyrinthError exception that reads:12

If the previous conditions hold but the further conditions spelled out above for the input to qualify as a

labyrinth (that is, the condition on the last digit on every line with digits and the condition on the digits on

the last line) do not hold, then the effect of executing lab = Labyrinth(filename) should be to generate a

LabyrinthError exception that reads:

If the input is correct and represents a labyrinth, then lab = Labyrinth(filename) followed by

lab.display_features() should have the effect of outputting the following:

the number of gates, that is, the number of consecutive points on one of the four sides of the

labyrinth that are not connected,

the number of sets of connected walls,
the number of inner points that cannot be accessed from any gate, starting from the point in the

middle of a gate and going from inner points to neighbouring inner points,

the number of maximal areas that can be accessed from at least one gate (the number of

accessible inner points is at most equal to the number of gates),

the number of accessible cul-de-sacs (a cul-de-sac is a maximal set S of connected inner points that

can all be accessed from the same gate g and such that for all points p in S, if p has been accessed

from g for the first time, then either p is in a dead end or moving on without ever getting back

leads into a dead end), and

the number of entry-exit paths with no intersections not to cul-de-sacs consisting of a maximal set

S of connected inner points that go from a gate to another (necessarily different) gate and such that

for all points p in S, there is only one way to move on from p without getting back and without

entering a cul-de-sac, in other words, the resulting path is choice-free, that is, such that leaving the

path, at any inner point where that is possible, immediately leads into a cul-de-sac.

The above should be displayed exactly as described below.

A first line that reads one of:

The labyrinth has no gate.

The labyrinth has a single gate.

The labyrinth has N gates.

with N an appropriate integer at least equal to 2.13

A second line that reads one of:

The labyrinth has no wall.

The labyrinth has walls that are all connected.

The labyrinth has N sets of walls that are all connected.