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CS 5 Today: two I's
AI UI
hw11pr2.py
an arbitrarily-good Connect 4 player!
Player class
Extra:
scoreBoard4Tourney
an intuitive Connect 4 player:
hw11pr1.html
I wish there were three i's!
Hw 11 is due Tuesday, 11/24
M/T 11/23-24 Introduction to final projects
After Thanksgiving TheoComp!
T 11/24 10pm Ex.Cr. circuits lab…
W 11/25 1:15pm Ex.Cr. circuits lab…
Schedule:
Epic winsFor?
Python had no Connect-four datatype…
| | | | | | | || | | | | | | || | | | | | | || | | |X| | | || |X| |X|O| | ||X|O|O|O|X| |O|--------------- 0 1 2 3 4 5 6
Looking further ahead?
… but you've already corrected that!
Two-player games have been a key focus of AI as long as computers have been around…
Strategic thinking == intelligence?
In 1945, Alan Turing predicted that computers
would be better chess players than people in
~ 50 years…
and thus would have achieved intelligence.
Alan Turing memorial Manchester, England
How humans play games…
- experts could reconstruct these perfectly - novice players did far worse…
An experiment (by A. deGroot) was performed in which chess positions were shown to novice and expert players…
How humans play games…
- experts could reconstruct these perfectly - novice players did far worse…
Random chess positions (not legal ones) were then shown to the two groups
- experts and novices did equally well (badly) at reconstructing them!
An experiment (by A. deGroot) was performed in which chess positions were shown to novice and expert players…
Two-player games have been a key focus of AI as long as computers have been around…
Strategic thinking == intelligence?
humanscomputers
good at evaluating the strength of a board for a player
good at looking ahead in the game to
find winning combinations of
moves
… humans and computers have different relative strengths in these games.
hw11 pr2
building an AI chess playeremulating a human by
evaluating a board position
ex. credit
Computer Chess…
Exam 2 solutionsProblem 1
def zerospan( L, hi, low ):
for i in range(len(L)):
if low <= L[i] <= hi:
L[i] = 0.0
This does not change L!
last time:
Exam 2 solutionsProblem 2
Hmmm Problem 3
Player data
PlayerpForX
What data does a computer AI player need?
Let's see a demo!
stringox
stringtbt
'X' 'LEFT'intply
0
DATA MEMBERS
tiebreakTypechecker, O or X moves to look ahead
surprisingly little!
How about knowledge about its opponent?
Player
Player methods
__init__(self, ox, tbt, ply)
__repr__(self)
scoreBoard(self, b)
scoresFor(self, b)
tiebreakMove(self, scores)
nextMove(self, b)
oppCh(self)
Board
__init__( self, width, height )
allowsMove( self, col )
__repr__( self )
addMove( self, col, ox )
isFull( self )
winsFor( self, ox )
hostGame( self )
delMove( self, col )
scoreBoard(self,b) ‘X’‘O’
Assigns a score to any board, b
100.0 50.0 0.0A simple system:for a win for a lossfor anything else
Score for Score for
Score for Score for
scoreBoard
Assigns a score to any board, b
100.0 50.0 0.0A simple system:for a win for a lossfor anything else
scoreBoard(self, b)
Implementation ideas…
What methods that already exist will come in handy?
This doesn't seem to be looking very
far ahead !
How can there be no 'X' or 'O' input?
What class is this method in?
Looking further ahead…
scoreBoard looks ahead 0 movesThe "Zen" approach --
we are excellent at this!
If you look one move ahead, how many possibilities are there to consider?
0-ply
1-ply
A 1-ply lookahead player will "see" an impending victory.
turn
A score for each
column…?
scores
p42.scoresFor( b42 )
special case
Two moves ahead… ?
A 2-ply lookahead player will also "see" an opponent's
impending victory.
's move…
What about 3-ply?
2-ply
1-ply score
score
p43.scoresFor( b42 ) and p44
scoresFor
scoreBoard looks ahead 0 movesThe "Zen" approach --
we are excellent at this!
If you look one move ahead, how many possibilities are there to consider?
0-ply
1-ply
scoresFor( self, b ) returns a LIST of scores, one for each column you might choose to move next…
2-ply
b
0-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
1-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
2-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
3-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
"Quiz" 'X'
'O'you - or self - is
playing 'O'
Name(s):
Fill in the N-ply score for a move to each column. The same move is evaluated at each ply! It's just evaluated farther into the future.
Looks 0 moves into the future
Looks 1 move into the future
Looks 2 moves into the future
Looks 3 moves into the future
|O| | | | | | ||X| | | |O| |X||O| | | |X|O|X||X| | | |O|O|X||X| |X| |X|O|O||X| |O|O|O|X|X|--------------- 0 1 2 3 4 5 6
| | | | | | |O|| | | | | | |O|| | | | | | |X||X| |X|O| | |O||X|O|O|X| |X|X||X|O|O|O| |O|X|--------------- 0 1 2 3 4 5 6
It is O’s move. What scores does a 1-ply lookahead for O assign to each
move? col 0 col 1 col 2 col 3 col 4 col 5 col 6
It is X’s move. What scores does a 2-ply lookahead for X assign to each
move?col 0 col 1 col 2 col 3 col 4 col 5 col 6
Which change at 3-ply?
Which change at 2-ply?
Example 1-ply and 2-ply lookahead scores
|O| | | | | | ||X| | | |O| |X||O| | | |X|O|X||X| | | |O|O|X||X| |X| |X|O|O||X| |O|O|O|X|X|--------------- 0 1 2 3 4 5 6
| | | | | | |O|| | | | | | |O|| | | | | | |X||X| |X|O| | |O||X|O|O|X| |X|X||X|O|O|O| |O|X|--------------- 0 1 2 3 4 5 6
It is O’s move. What scores does a 1-ply lookahead for O assign to each
move? col 0 col 1 col 2 col 3 col 4 col 5 col 6
It is X’s move. What scores does a 2-ply lookahead for X assign to each
move?
col 0 col 1 col 2 col 3 col 4 col 5 col 6
be careful!
-1 100 50 100 50 100 50
100 0 0 0 50 0 -1
Which change at 2-ply? 0 0
Which change at 3-ply?0
Answers to example lookahead scores
‘X’‘O’new‘X’
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b
scoresFor each column
(1) For each possible move
(2) Add it to the board
(self) 'X'
'O'
new 'X'
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT its scoresFor each board!
At what ply?
[50,50,50,50,50,100,50]
[ 0, 0, 0, 0, 0, 0, 0 ]
scoresForneeds to return a list of 7 numbers for self
these are all of the opponent's evaluations of its next move…
[ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ]
[50,50,50,50,50,50,50]
[50,50,50,50,50,100,50]
(self) 'X'
'O'
new 'X'
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT its scoresFor each board!
At what ply?
[50,50,50,50,50,100,50]
[ 0, 0, 0, 0, 0, 0, 0 ]
scoresForneeds to return a list of 7 numbers for self
these are all of the opponent's evaluations of its next move…
[ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ]
[50,50,50,50,50,50,50]
[50,50,50,50,50,100,50]
What score does the opponent give
each?
(self) 'X'
'O'
new 'X'
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT its scoresFor each board!
At what ply?
[50,50,50,50,50,100,50]
[ 0, 0, 0, 0, 0, 0, 0 ]
scoresForneeds to return a list of 7 numbers for self
these are all of the opponent's evaluations of its next move…
[ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ] [ 0, 0, 0, 0, 0, 0, 0 ]
[50,50,50,50,50,50,50]
[50,50,50,50,50,100,50]
What score does the opponent give
each?
max(S) = 0
max(S) = 100
max(S) = 0max(S) = 0
max(S) = 0max(S) = 50
max(S) = 100
What score does self give each?
100
0100
100 10050
0
Difficulty == Branching Factor
Branching Factor Estimatesfor different two-player games
Tic-tac-toe 4
Connect Four 7
Checkers 10
Othello 30
Chess 40
Go 300
• On average, there are fewer than 40 possible moves that a chess player can make from any board configuration…
0 Ply
1 Ply
2 Ply
Hydra at home in the United Arab Emirates…
Hydra looks ahead 18 ply !What do you think, Noam?
500
1200
2000
2800
Computer Chess
early programs ~ 1960’s
Computers cut their teeth playing chess…
Ranking
beginner
amateur
world ranked
world champion
MacHack (1100) ~ 1967 MIT
Deep Thought ~ 1989 Carnegie Mellon
Slate (2070) ~ 1970’s Northwestern
Deep Blue ~ 1996 IBM
Deep Blue rematch ~ 1997 IBM
100’s of moves/sec
10,000’s of moves/sec
1,000,000’s moves/sec
3,500,000 moves/secDeep Fritz: 2002X3D Fritz: 2003 Hydra: 2006
200,000,000 moves/sec
first paper: 1950
What is Hydra's chess rating?
Games’ Branching Factors
Branching Factor Estimatesfor different two-player games
Tic-tac-toe 4
Connect Four 7
Checkers 10
Othello 30
Chess 40
Go 300
1 Ply
2 Ply
Boundaries for qualitatively different games…
0 Ply
Games’ Branching Factors
Branching Factor Estimatesfor different two-player games
Tic-tac-toe 4
Connect Four 7
Checkers 10
Othello 30
Chess 40
Go 300
“solved” games
computer-dominated
human-dominated
1 Ply
2 Ply
0 Ply
Progress
def scoresFor(self, b):(1) For each possible move
(2) Add it to the board b
(3) Ask OPPONENT its scoresFor each b at ply-1
(4) self's score is 100-max!
Write tiebreakMove to return the leftmost best score
inside the list scores
def tiebreakMove(self, scores):
if self.tbt == 'LEFT':
How would 'RANDOM' and 'RIGHT' work differently?
hw11 this week
• Extra: scoreBoard4Tourney and a CS 5 C4 round-robin
http://www.stanford.edu/~ccecka/research/C4.html
Using more scores than 0, 50, and 100 !
• Problem 2: A Connect Four Player…
don't give this board a 50.0 !
• Problem 1: (Lab) Trying out a command-line user interface
User Inferfaces
No undo!
% ls
file1.txt file2.txt
file3.txt !
% rm *!
(long pause…)
Design for software and beyond
0. Conceptual
models
1. Mapping
2. Visibility
3. Feedback
4. Affordances
Don Norman's key principles:
Conceptual Models
Users always bring something "to the table"
these don't work!
Images from The Design of Everyday Things
Mapping
is matching expected (spatial) relationships
Where to plug in the keyboard and mouse?
?
Visibility
is making functionality apparent
Shower?Slide projector…
From: www.baddesigns.com
"I used to have that awful shower controller where you pull down on the nozzle to turn it on. I had to tell every guest how to do it, and when we sold our house, we got a call from the new owners about 5 days later asking how to turn on the shower. They had been taking baths for 5 days! Unbelievable." - BL
Feedback
providing information back to the user
from the UI Hall of Shame
Microsoft Access
Microsoft Outlook
http://homepage.mac.com/bradster/iarchitect/shame.htmBut some of us graphics aren't so lazy!
Affordances
are the functions that form suggests…
Opening the XO? Door handles
built-in user's manual
Where do these go wrong?Mapping
How to open this gas cap?
Visibility Feedback Affordances
This handle unfastens the seat from the
floor.
How to turn on this stove?
Set to 5 minutes?
Win NT Dialog
The designers aren't the users…
See you on Monday!
Remember: CS Hw #11 is due next Tuesday…
Thinking about User Interfaces
Command Line Tablet / Touch
Ambient Information
Display Walls
Thinking about User Interfaces
What other types of human/computer interfaces can you think of?
#1 WI
MP
indowsconsenusointer
GUI
Affordances~ physical and cultural expectations
0. Conceptual models 1. Mapping
Matching user expectations e.g., Directory structures
Visibility and Feedback
Banks of glass doorsSlide projector
Affordances The functions that form suggests! Phone settings
Why is this a better design?
Keypad numbers layout
• A case of external inconsistency
1 2 34 5 6
7 8 9
7 8 9
1 2 3
4 5 6
0 0
(a) phones, remote controls(b) calculators, computer keypads
Affordances: to give a clue• Affordances: The perceived and actual properties of an object that signal of the object can be used (from The Design of Everyday Things)
Physical Affordances
Physical Affordances
What do the Zune wheel and the door handle have in common?
Virtual AffordancesClick Me Click Me
"Quiz"
Name(s):
Note the perceivedaffordances inthis interface.Are there anythat are missing?Misleading?
0-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
1-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
2-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
3-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
Solutions
-1
-1
-1
-1
50 50 50 50 50 50
50 50 100 50 50 50
0
0
100
100
0
0
0 0 50
100
00
b ‘X’‘O’
|O| | | | | | ||X| | | |O| |X||O| | | |X|O|X||X| | | |O|O|X||X| |X| |X|O|O||X| |O|O|O|X|X|--------------- 0 1 2 3 4 5 6
It is O’s move. What scores does a 1-ply lookahead for O assign to each
move? col 0 col 1 col 2 col 3 col 4 col 5 col 6
Which change at 2-ply?
Looking further ahead …
0 ply:
2 ply: 3 ply:
Zen choice of move: here and now
| | | | | | | || | | | | | | ||O| | | | | | ||X| | | | | | ||X|O|O| | |X| ||O|X|X|O|X|O| |--------------- 0 1 2 3 4 5 6
| | | | | | | || | | | | | | || | | | |X| | || | | | |O|O| || |X|X| |X|O| ||O|X|O| |O|X| |--------------- 0 1 2 3 4 5 6
(1) Player will win
(2) Player will avoid losing
(3) Player will set up a win by forcing the opponent to avoid losing
X’s move
X‘s move
1 ply:
| | | | | | | || | | | | | | || | | | | | | || | | | | | | || |O|X| | | | ||O|X|X|X| |O|O|--------------- 0 1 2 3 4 5 6
X’s move
‘X’‘O’new‘X’
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT to score each board
(4) Which score will the opponent choose?
0.0
50.0
0.00.0
50.0
0.0
What, then, should assign for your score? (self's score)
scoresFor each column
50.0
‘X’‘O’new‘X’
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b
Choosing the best move
(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT to score each board - ply?
(4) Reverse the scores
100.0
50.0
50.0
100.0100.0
50.0
100.0
‘X’‘O’new‘X’
Col 6
Col 5
Col 4Col 3Col 2
Col 1
Col 0
b
Choosing the best move
100.0
50.0
50.0
100.0100.0
50.0
100.0
(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT to score each board - ply?
(4) Reverse the scores
(5) Find one max - that's it!
Connect Four
| | | | | | | || | | | | | | || | | | | | | || | | |X| | | || |X| |X|O| | ||X|O|O|O|X| |O|--------------- 0 1 2 3 4 5 6
Suppose our Board class's 2d list of lists is named self.data. What is the
name of this single spot?
For your convenience, the creators of Python’s library have included a Board class that can represent any size of Connect Four board... !
Connect Four: the object b
This is true for sufficiently broad definitions of “the creators of Python’s library” ...
Boardb
def addMove(self, col, player)
intNROWS
intNCOLS
def allowsMove(self, col)
char char char
char char char
char char char
datalist char
char
char
def winsFor(self, player)
data members
methods
What is player ?
Connect Four: the object b
This is true for sufficiently broad definitions of “the creators of Python’s library” ...
Boardb
def addMove(self, col, player)
intNROWS
intNCOLS
def allowsMove(self, col)
char char char
char char char
char char char
datalist char
char
char
def winsFor(self, player)
data members
methods
Which methods will alter b? Which leave it alone?
Connect Four: Board
Starting code for the Board class
class Board: def __init__( self, numRows, numCols ): """ our Board's constructor """ self.NROWS = numRows self.NCOLS = numCols self.data = [] for r in range(self.NROWS): onerow = [' ']*self.NCOLS self.data += [onerow]
def __repr__(self): """ thoughts? """
look familiar?
Connect Four: Boardclass Board: def __init__( self, numRows, numCols ): """ our Board's constructor """ self.NROWS = numRows self.NCOLS = numCols self.data = [] for r in range(self.NR): onerow = [' ']*self.NC self.data += [onerow]
def __repr__(self): """ thoughts? """ s = '\n' for r in range(self.NROWS): s += '|' for c in range(self.NCOLS): s += self.data[r][c] + '|'
return s
look familiar?
a bit more to go !
Problem 2
class Board
__init__
allowsMove
__repr__
addMove
isFull
winsFor
the “constructor”
checks if allowed
places a checker
outputs to screen
checks if space left
checks if a player has won
Hw11 Pr2: Connect Four Board
hostGame play!
What's trickiest here?
Problem 2
class Board
__init__
allowsMove
__repr__
addMove
isFull
winsFor
the “constructor”
checks if allowed
places a checker
outputs to screen
checks if space left
checks if a player has won
Hw11 Pr2: Connect Four Board
hostGame play!
What's trickiest here?
What's wrong here?
| | | | | | | || | | | | | | || | | | | | | || | | |O|O| | ||X|X| |O|X|X|X||X|O|O|O|O|X|X|--------------- 0 1 2 3 4 5 6
def winsForHoriz(self, player): inarow = 0
for r in range(self.NROWS): for c in range(self.NCOLS):
if self.data[r][c] == player: inarow += 1 else: inarow = 0
if inarow == 4: return True
return False
Strategies?
horizontals
verticals
diagonals ??| | | | | | | || | | | | | | || | | | | | | || | | |O|O| | ||X|X| |O|X|X|X||X|O|O|O|O|X|X|--------------- 0 1 2 3 4 5 6
“Quiz”
class Board{ # __init__ and __repr__ methods here… # 3 data members: # self.NR == number of rows # self.NC == number of cols # self.data == the 2d list of lists of chars
def mysteryMethod(self, col, ox): r = 0 while r < self.NR and self.data[r][col] == ' ': r += 1 self.data[r-1][col] = ox
def allowsMove(self, col):
}
Briefly, what is each line of the
mysteryMethod doing? Which method is it?
Write allowsMove to return whether the input col is a valid column to move.
(True or False)
1
2
3
Could it go wrong?
Problem 2
class Board
__init__
allowsMove
__repr__
addMove
isFull
winsFor
the “constructor”
checks if allowed
places a checker
outputs to screen
checks if space left
checks if a player has won
Hw11 Pr2: Connect Four Board
hostGame play!
What's trickiest here?
def scoresFor(self, b):(1) For each possible move
(2) Add it to the board
(3) Ask OPPONENT to score each board at ply-1
(4) self's score is 100-max
Problem 2
class Board
__init__
allowsMove
__repr__
addMove
isFull
winsFor
the “constructor”
checks if allowed
places a checker
outputs to screen
checks if space left
checks if a player has won
Hw11 Pr2: Connect Four Board
hostGame play!
What's trickiest here?
Strategies?
horizontals
verticals
diagonals ??| | | | | | | || | | | | | | || | | | | | | || | | |X| | | || |X| |X|O| | ||X|O|O|O|O| |O|--------------- 0 1 2 3 4 5 6
|O| | | | | | ||X| | | |O| |X||O| | | |X|O|X||X| | | |O|O|X||X| |X| |X|O|O||X| |O|O|O|X|X|--------------- 0 1 2 3 4 5 6
It is O’s move. What scores does a 1-ply lookahead for O assign to each
move? col 0 col 1 col 2 col 3 col 4 col 5 col 6
Which change at 2-ply?
Example 1-ply and 2-ply lookahead scores
0-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
1-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
2-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
3-ply scores for O:
col 0 col 1 col 2 col 3 col 4 col 5 col 6
Solutions
-1
-1
-1
-1
50 50 50 50 50 50
50 50 100 50 50 50
0
0
100
100
0
0
0 0 50
100
00
b ‘X’‘O’
Connect Four: the object b
Boardb
intwidthstr str str
str str str
str str str
datalist str
str
str
data
intheight
What is the name of the method that will construct this data?
Connect Four: constructor
class Board: """ a datatype representing a C4 board with an arbitrary number of rows and cols """ def __init__( self, width, height ): """ the constructor for objects of type Board """ self.width = width self.height = height self.data = [] # this will be the board for row in range( 6 ): boardRow = [] for col in range( 7 ): boardRow += [' '] # add a space to this row self.data += [boardRow]
Bad magic?
Connect Four: the object b
Boardb
intwidthstr str str
str str str
str str str
datalist str
str
str
intheight
| | | | | | | || | | | | | | || | | | | | | || | | |X| | | || |X| |X|O| | ||X|O|O|O|X| |O|--------------- 0 1 2 3 4 5 6
What is the name of the method that will print this data?
def __repr__(self): """ this method returns a string representation for an object of type Board """ s = '' for row in range( 6 ): s += '|' for col in range( 7 ): s += self.data[row][col] + '|' s += '\n'
return s
Connect Four: __repr__
To remove?
To add?
which row is row 0, row 1, and so on?
Examples
def addMove(self, col, ox):
row = self.height-1 while True: if self.data[row][col] == ' ': self.data[row][col] = ox
row -= 1
def allowsMove(self, col):
Step through this addMove method.
How does it work?
What's wrong?
a C4 board
col #'X' or 'O'
allowsMove should return True if col is a valid move;
False otherwise.
C4 Board class: methods
__init__( self, width, height )
allowsMove( self, col )
__repr__( self )
addMove( self, col, ox )
isFull( self )
winsFor( self, ox )
the “constructor”
checks if allowed
places a checker
outputs a string
checks if any space is left
checks if a player has won
hostGame( self )play!
delMove( self, col )removes a checker
Which is trickiest… ?
Checking wins… ?
Thought
s?
X O
b
corner cases?
A whole new class of programming
CS 5 today
Mon., 11/26Wed., 11/28
Mon., 12/3
Software Engineering
Final projects
TheoComp !
Exam review
Python's Date class
Wed., 12/5Mon., 12/10
Lab and HW #11
Hey! How did you get a
body?
Choose your side…
Exam 2
Exam 2
Problem 1b Problem 2
def zerospan( L, hi, low ):
for i in range(len(L)):
if low <= L[i] <= hi:
L[i] = 0.0
def zerospan( L, hi, low ):
for x in L:
if low <= x <= hi:
x = 0.0
def ROOKnotcastle( B, r, c ):
for row in range(len(B)):
for col in range(len(B[0])):
if row == r or col == c:
B[row][col] = 1
This does not change L!
def zerospan( L, hi, low ):
for x in L:
if low <= x <= hi:
x = 0.0
CAUTION: This does not change L!
Sets values between low and hi to 0.0.
Exam 2Problem 3
00 read r1 # input to r1
01 add r2 r2 r1 # add into r2
02 jnez r1 00 # if r1 != 0: goto 00
03 write r2 # else: write the sum
using the stack -- Aargh!adding in place :-)
Exam 2Problem 5
ruler( 1 )
ruler( 2 )
'1'
'212'
ruler( 3 ) '3231323'
ruler( 4 ) '434243414342434'
s si
def ruler( n ):
s = ''
for i in range(n,0,-1):
s += str(i) + s
return s
Exam 2
Exam 2
A whole new class of programming
CS 5 today
Mon., 11/26Wed., 11/28
Mon., 12/3
Software Engineering
Final projects
TheoComp !
Exam review
Python's Date class
Wed., 12/5Mon., 12/10
Lab and HW #11
Hey! How did you get a
body?
Choose your side…
Exam 2
Exam 2
Exam 2
Two-player games have been a key focus of AI as long as computers have been around…
Strategic thinking == intelligence?
… humans and computers have different relative strengths in these games.
humanscomputers
good at evaluating the strength of a board for a player
good at looking ahead in the game to
find winning combinations of
moves
