Nim¶
Nim is a strategy game between two players.
Start by placing counters (coins or toothpicks or something) into 3 piles.
Player #1 picks a pile, then removes one or more counters from that pile. (It’s okay to take the whole pile.)
Player #2 picks a pile, then removes one or more counters from that pile.
Player #1 plays again. (It’s okay to choose a different pile this time.)
Whichever player is forced to take the last counter is the LOSER.
Write a program that allows two human players to play Nim against each other. The program should detect when the last counter has been taken and declare a winner.
At first, don’t worry about detecting cheating. That is one of the bonus options.
Name your file 063c_nim.py
Sample Output¶
Here is an example game, with starting piles of 3, 4, and 5 counters.
Player 1, enter your name: Alice
Player 2, enter your name: Bob
A: 3 B: 4 C: 5
Alice, choose a pile: A
How many to remove from pile A: 2
A: 1 B: 4 C: 5
Bob, choose a pile: C
How many to remove from pile C: 3
A: 1 B: 4 C: 2
Alice, choose a pile: B
How many to remove from pile B: 1
A: 1 B: 3 C: 2
Bob, choose a pile: B
How many to remove from pile B: 1
A: 1 B: 2 C: 2
Alice, choose a pile: A
How many to remove from pile A: 1
A: 0 B: 2 C: 2
Bob, choose a pile: B
How many to remove from pile B: 1
A: 0 B: 1 C: 2
Alice, choose a pile: C
How many to remove from pile C: 2
A: 0 B: 1 C: 0
Bob, choose a pile: B
How many to remove from pile B: 1
A: 0 B: 0 C: 0
Alice, there are no counters left, so you WIN!
Bonus #1 - Cheat Protection¶
For +30 bonus points, prevent the users from doing anything bad:
...a game already in progress.
A: 0 B: 1 C: 0
Bob, choose a pile: A
Nice try, Bob. That pile is empty. Choose again: B
How many to remove from pile B: 0
You must choose at least 1. How many? 1
A: 0 B: 0 C: 0
And what about this?
A: 1 B: 4 C: 5
Bob, choose a pile: C
How many to remove from pile C: 8
Pile C doesn't have that many. Try again: 3
A: 1 B: 4 C: 2
And don’t forget this:
A: 1 B: 4 C: 5
Bob, choose a pile: C
How many to remove from pile C: -2
You must choose at least 1. How many? 3
A: 1 B: 4 C: 2
Bonus #2 - Dignity¶
For +10 bonus points, make your program detect when there is only one counter left and declare the winner one turn earlier.
...a game already in progress.
A: 0 B: 2 C: 2
Bob, choose a pile: B
How many to remove from pile B: 1
A: 0 B: 1 C: 2
Alice, choose a pile: C
How many to remove from pile C: 2
A: 0 B: 1 C: 0
Bob, you must take the last remaining counter, so
you lose. Alice wins!
Bonus #3 - Fancy Display (Rows)¶
For +15 bonus points, visually display the counters in rows instead of just showing a number. You must use loops for this.
A: ***
B: ****
C: *****
Alice, choose a pile: A
How many to remove from pile A: 2
A: *
B: ****
C: *****
Bob, choose a pile: C
How many to remove from pile C: 3
A: *
B: ****
C: **
Bonus #4 - Fancy Display (Columns)¶
For +25 bonus points, visually display the counters in columns. You must use a loop for this.
This is quite difficult.
*
* *
* * *
* * *
* * *
A B C
Alice, choose a pile: A
How many to remove from pile A: 2
*
* *
* *
* *
* * *
A B C
Bob, choose a pile: C
How many to remove from pile C: 3
*
*
* *
* * *
A B C
Bonus #5 - Computer Opponent¶
For +50 bonus points, allow one human player to play against a computer opponent. The computer must attempt to win and not break any rules.
It is possible to make a computer player that ALWAYS wins if it goes first. The Wikipedia article for Nim explains the theory.
However, your program does not need to use a winning strategy to earn bonus points: it merely must make only legal moves.
©2013 Graham Mitchell
This assignment is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.
