Question

Refactor the following code (it's one of the most straightforward functions you can create in Python):
def fact(x):
ans = 1
n = 2
while n <= x:
ans *= n
n += 1
return ans

Answer 1

Also refactor the following to make them faster

nPr = lambda x,y: fact(x)/fact(x-y)
nCr = lambda x,y: nPr(x,y)/fact(y)

Answer 2

also, please help me compolete this project. I couldn't figure it out :(

"""
TIC-TAC-TOE

In the default implementation of TicTacToe, the Computer opponent never loses.

The class hierarchies are as follows:

Object ## All classes inherit from Object.
Game ## You subclass Game to get the game you want.
TicTacToe
Player ## You subclass Player to get the player you want.
ComputerPlayer
HumanPlayer
GameRoom

"""

# TO DO:
# Implement the abstract Object class correctly.
# Implement the Game class correctly.
# Implement a TicTacToe class correctly.
# Implement the Player class correctly.
# Implement the HumanPlayer class correctly.
# Implement the ComputerPlayer class correctly.
# Implement the GameRoom class correctly.
# Implement variants of the TicTacToe Game where the computer does lose.
# Implement computer-only games of TicTacToe
# Implement player-only games of TicTacToe
# Implement a GUI correctly.

#______________________________________________________________________________
#
# Imports:

import random

#______________________________________________________________________________

class Object(object):
"""
Class Template. All objects inherit from this class.
"""
def __repr__(self):
return '<%s>' % getattr(self, '__name__', self.__class__.__name__)

def printClassInfo(self):
print self.__doc__

def printClassMethods(self):
methodlist = dir(self)
dirlength = len(methodlist)
for index in xrange(dirlength):
print '%d. %s' % (index+1, methodlist[index])
print

def test(self):
"""
Abstract test method.
"""
print "I don't know how to test your class."

#______________________________________________________________________________

class Game(Object):
"""
Some abstract methods for Game objects.
"""
def newGame(self):
"""
Starts a new game.
"""
print "I don't know how to start a new game."

#______________________________________________________________________________

class TicTacToe(Game):
"""
This class simulates the game of Tic-Tac-Toe with a 3x3 board,
storing the state of the board as well as checking to see if the
board is in a 'won' state.

By default, computer should never lose.

The 3x3 Tic-Tac-Toe board is implemented as a list of 3 lists, each
containing 3 elements corresponding to the state of the board.

0 corresponds to a blank tile.
1 corresponds to an X on the tile.
-1 corresponds to a O on the tile.
"""
def __init__(self):
self.moveset = {7:0,8:1,9:2,4:3,5:4,6:5,1:6,2:7,3:8}
self.emptyBoard()
self.winner = 0
self.validstates = [-1, 0, 1]
self.states = {-1:'O', 0:' ', 1:'X'}
self.humanstate = self.states[1]
self.computerstate = self.states[-1]

def emptyBoard(self):
"""
Sets the board to the empty, initial state.
Used to initialize the board at the beginning of the game,
as well as during the initialization of the TicTacToe instance.
"""
self.board = [[0,0,0],[0,0,0],[0,0,0]]

def setBoard(self, board):
"""
This method enables the specification of a board with predetermined
states.
"""
# Might change it so that only lists of -1, 0, or 1 are allowed
self.board = board

def getBoard(self):
"""
Returns a list of lists, with each list corresponding to a row
within the Tic-Tac-Toe board.
"""
return self.board

def setTile(self, row, column, state):
"""
Alters the state of a board tile at a particular position.
Returns if the state argument is not a valid state.
"""
if state in self.validstates:
self.board[row][column] = state

def getTile(self, row, column):
"""
Returns the state of the board tile at a particular position.
The value returned is an integer that is either -1, 0, or 1.
"""
return self.board[row][column]

def displayBoard(self):
"""
Prints out the board on the console output.
"""
print "_____"
for row in xrange(3):
for column in xrange(3):
print "%s" % (self.states[self.getTile(row, column)]),
print
print "_____"

def checkWinner(self):
"""
This method checks the board to see if the states in the board
satisfy the winning conditions of Tic-Tac-Toe.
Returns the winning state (-1 or 1) of the board if the game is won.
Otherwise, returns 0.
"""
for i in xrange(3):
if (self.getTile(i,0) and
self.getTile(i,1) == self.getTile(i,0) and
self.getTile(i,2) == self.getTile(i,0)):
return self.getTile(i,0)
if (self.getTile(0,i) and
self.getTile(1,i) == self.getTile(0,i) and
self.getTile(2,i) == self.getTile(0,i)):
return self.getTile(0,i)
if not self.getTile(1,1):
return 0
if (self.getTile(1,1) == self.getTile(0,0) and
self.getTile(2,2) == self.getTile(0,0)):
return self.getTile(0,0)
if (self.getTile(1,1) == self.getTile(2,0) and
self.getTile(0,2) == self.getTile(1,1)):
return self.getTile(1,1)
return 0

def displayState(self, statenumber):
"""
Returns the state (string) corresponding to the statenumber (int).
Returns None if the state is blank i.e. 0.
"""
return self.states[statenumber]

def playRound(self):
"""
Plays one round of the Tic-Tac-Toe game.
"""
self.emptyBoard()
print "Board positions are numbered as:\n1 2 3\n4 5 6\n7 8 9"
print "\nOn the numpad, those are:\n7 8 9\n4 5 6\n1 2 3"
print "\nYou have %s, I have %s.\n" % (self.humanstate,
self.computerstate)

def test(self):
"""
Test method used to test other methods.
"""
self.setBoard([[1,1,1],[0,0,0],[0,0,0]])
self.displayBoard()
print self.checkWinner()
self.setBoard([[-1,0,0],[-1,0,0],[-1,0,0]])
self.displayBoard()
print self.checkWinner()

#______________________________________________________________________________

class Player(Object):
"""
Template for both the human and the computer player.
"""
pass

class ComputerPlayer(Player):
"""
Template for the computer player.
"""
def __init__(self):
pass

class HumanPlayer(Player):
"""
Template for the human player.
"""
def __init__(self):
pass

#______________________________________________________________________________

class GameRoom(Object):
"""
An environment for the Tic-Tac-Toe game.
"""
def __init__(self):
pass

def announceWinner(self):
pass

def playGame(self):
pass

#______________________________________________________________________________
#
# Top Level Functions:

def main():
"""
Entry point.
"""
thegame = TicTacToe()
thegame.playRound()
thegame.test()

if __name__ == '__main__':
main()

#______________________________________________________________________________

Answer 3

http://ideone.com/PmL3q