CPSC 231 - Fall XXXXXXXXXXUniversity of Calgary
cpsc 231 assignment #5
Taffy Tangle
If you’ve ever played casual games on your mobile device, or even
on the internet through your
owser, chances are that you’ve spent
some time with a “match three” game. Of the recent varieties, Candy
Crush Saga, published by King in 2012 and shown in Figure 1, has
een one of the most wildly successful titles for mobile platforms.
Figure 1: Candy Crush Saga is an
incredibly popular match-three game
that has provided billions of hours of
entertainment to the world.
Figure 2: Bejeweled is another popula
variant of the match-three game whose
first version was released a full decade
efore Candy Crush Saga.
The goal of this assignment is to create our own simple variant
of a match-three game, which we’ll call “Taffy Tangle.” (Feel free to
call yours whatever you’d like. We just made this one up to create a
consistent alliteration through the problems of this assignment.)
The base mechanics of a match-three game are quite simple. A
(usually) rectangular board is initially filled with a grid of randomly-
selected objects from a prescribed set. There are usually five or six
varieties of these objects (be they candies, jewels, or other things)
which are visually differentiated by their colour and shape.
After the initial board set-up, the player makes a move by swap-
ping two adjacent objects so that a line (horizontal or vertical) of at
least three objects of the same kind is made. Then all lines of at least
three adjacent objects of the same kind are eliminated and a score
proportional to the number of objects eliminated is added to the
player’s total. Remaining objects “fall” from top to bottom to fill the
gaps created by the eliminated objects, and random new objects are
created at the top to fill up the board again. Any new lines of three
or more matches are again eliminated, and the falling and random
creation process is repeated until there are no more matches. The
player then continues to make moves until a certain objective (e.g.
score) is met, or no valid moves remain.
It’s hard to make sense of such a ve
al description, so if you
haven’t played Candy Crush or Bejeweled before, we encourage you
to try them out. They are free to play, though be forewarned that
they can be quite addictive. Don’t forget about your assignment!
Due Dates
Individual component Friday, November 9, 11:59 pm
Paired component Friday, November 23, 11:59 pm
2 cpsc 231 - fall XXXXXXXXXXuniversity of calgary
Individual Component
We’re now down to a single problem for each component of the
assignment! By this point in the course, we trust that you’re a well-
trained computer scientist1 who doesn’t need our help anymore to 1 Or perhaps an expert compute
scientist in training?apply the principles of top-down design and stepwise refinement to
solving computing problems. It is entirely up to you now to exercise
your skills as a computer scientist and devise algorithms to solve the
problems, then plan out the structure and layout of your program,
efore you implement your solutions as Python programs.
We believe these initial steps are best done with a pencil and a
pad of paper, and we strongly recommend that you spend at least
half of your time for each problem on this step. Although you’re not
equired to hand this in, don’t say we didn’t warn you if you decide
to skip this step!
You can use the exact same programming environment you set
up for previous assignments to complete this assignment. Create
as many modules or classes as you wish to help you organize you
code, but be sure to submit all your .py files and indicate clearly
which script (program file) your ta should run for each problem.
Note also that the bonus problem for this assignment is attached to
the individual component rather than the paired component.
Problem 1: Tic-Tac-Toe
Tic-Tac-Toe is another classic two-player game, played on pencil and
paper, that most of us surely learned before elementary school. It is
played on a three-by-three grid of squares as shown in Figure 3, and
the object of the game is to claim a row of three squares on the board,
either horizontally, vertically, or diagonally.
Figure 3: A Tic-Tac-Toe game in
progress.
Figure 4: Player × has won the game by
forming a line of three.
The player who goes first is known as × and the second playe
as #. The first player starts by claiming one of the nine squares by
marking it with an ×. Then the second player takes an open square
y marking it with an #. The players continue to alternate turns this
way until one player, the winner, makes a line of three squares in a
ow with his or her symbol, or until all nine squares are filled. If the
grid is filled but neither player has a line of three, the game is a draw
(also known as a “cat’s game”).
Create a visual and interactive Python program that will facili-
tate a game of Tic-Tac-Toe between two human players. Draw the
oard on the screen and wait for the first player to click in one fo the
nine squares, then draw an × in that square. Next, allow the second
player to do the same with an #. Write a message in your game’s
window to indicate whose turn it is. Continue until one of the play-
ers wins, or the game ends in a draw. Indicate the the final result of
the game in the graphics window, then wait until the players close
the window (or ask if the players would like to play another game).
assignment #5: taffy tangle 3
Inputs: A series of mouse clicks from two human players taking
turns to place their ×’s and #’s.
Outputs: A Tic-Tac-Toe board (which looks like a #) drawn in a win-
dow on your screen with ×’s and #’s drawn as they are placed.
Figure 5: The game is drawn when all
squares are filled and neither player has
a line of three.
Bonus Problem: Computer Tic-Tac-Toe Playe
Program a computer artificial intelligence capable of playing Tic-Tac-
Toe so that you can create a single-player version of your game from
Problem 1. Your ai must have at least two distinct difficulty levels:
Hard should be able to play a perfect, or near-perfect, game of Tic-
Tac-Toe. It should be able to force a draw against the human
player every time, and take a win if the player makes a mistake.
Moderate should make a mistake or sub-optimal move once in a
while to give the human player a chance of winning, but still play
a decent game. This difficulty ought to be great for small children.
You may either use a command line argument to select the ai
difficulty level or have the player click on a “button” to choose the
difficulty at the beginning of the game. Simulate a coin toss to decide
whether the human player will be × or #. Then play the game out
interactively just as you did for Problem 1, indicating the end result
in your game’s window as appropriate.
Inputs: A series of mouse clicks from the human player to place his
or her ×’s or #’s.
Outputs: A Tic-Tac-Toe board drawn in a window on your screen
with ×’s and #’s drawn as they are placed by the human and
computer players.
Paired Component
We strongly encourage you to work with a partner to complete the
emainder of this assignment. It will likely be extremely helpful to
have someone with whom to talk through the strategies for solving
this problem, and its sub-problems, as you do the top-down design
and program decomposition for this component.
Once again, your partner may be any other student in the class,
ut remember that you must work with a different partner for each
assignment! If you are solving this problem as a pair, one submission
is sufficient for both students. If you’ve already exhausted all you
friends in this class through the first four assignments, perhaps you
can ask your ta to help you with match-making. Maybe even try
hunting for your best movie match from Assignment #3.
4 cpsc 231 - fall XXXXXXXXXXuniversity of calgary
Problem 2: Taffy Tangle
Your goal for this problem is to a visual and interactive Python pro-
gram that allows a human player to play our variant of the match-
three game, Taffy Tangle (or whatever you’ve christened your game).
Our basic variant of the game will be played on a board measuring
9 rows by 7 columns with six different kinds of “taffies”, as shown
in Figure 6. The player makes moves by swapping adjacent taffies so
that a line (horizontal or vertical) of at least three objects of the same
kind is made. The game ends when no more valid moves remain.
Figure 6: The initial board of taffies in
our game, with one taffy selected (in-
side the red box), ready to be swapped.
Figure 7: The green taffy has been
swapped with the yellow one below,
creating two lines of three matches.
Figure 8: The two lines of matching
taffies have been eliminated, leaving a
gap in the middle.
Your program must be able to perform the following functions to
satisfy all requirements of this problem:
1. Generate an initial board (9 rows by 7 columns) filled with ran-
dom selections of the 6 different kinds of taffies, and draw the
oard to the screen.
• Each kind of taffy must be visually distinct from the others in
oth colour and shape. (Yours do not need to look like the ones
shown as long as they meet this requirement.)
• The initial board should not contain any lines (horizontal o
vertical) of three or more taffies of the same kind in a row.
2. Allow the player to make moves of swapping two adjacent taffies
on the board by first clicking on one taffy, then clicking on an
adjacent one, while the game is not won or lost.
• After the first click, indicate which taffy is “selected” in some
visual way (e.g. as shown in Figure 6).
• Cancel the move if the player then clicks a second taffy that is
not adjacent to the first, selected one.
• Fo
id or undo a move that would not result in creating a new
match of three or more taffies.
3. After a valid move from the player, repeatedly eliminate taffies
that are matched by following the sequence of steps below, until
no more matches are found. Update the visual board and pause
iefly after each step so that the player can see what happened.
• Eliminate all taffies on the board that are part of a horizontal o
vertical line of three or more taffies of the same kind (Figure 8).
• Allow taffies in each column to “fall” so that it contains a con-
tinuous stack of taffies from