Four in a row

# usage:

# width and height # defines the width and height of the board (should only be set when not playing, before init is called)

# player # 1 or 2 showing whos turn it is (player id), player 1 starts

# board # current board state. used as board[x][y], containing 0 if empty, or player id

# winner # 0 if no winner, else player id

# state # "NotInitialized" before first init, "Playing" while playing and "Tie", "Player1Won" or "Player2Won" if the game has ended

# init() # starts a new game

# get_available_cols() # returns a list of all possible values of 'col', used in drop_disc(col)

# drop_disc(col) # this drops a disc for current player in column 'col' (index 0)

# functions used "behind the scenes"

# set_winner() # checks if the grid contains a winner and, if that is the case, sets the "winner" variable to that player

# resolve_state() # sets state to a winning state if state is "Playing" and if the game should be considered over

width = 7

height = 6

player = 1

board = []

winner = 0

state = "NotInitialized"

def init():

global state

global player

global winner

global board

player = 1

winner = 0

state = "Playing"

board = [[0] * height for _ in range(width)]

def get_available_cols():

if state == "Playing":

return [x for x in range(len(board)) if sum(1 for v in board[x] if v > 0) < height]

else:

return []

def drop_disc(col):

global player

if state != "Playing":

return False

col_height = sum([1 for x in board[col] if x > 0])

if col >= 0 and col < width and col_height < height:

board[col][col_height] = player

player ^= 3

resolve_state()

return True

# behind the scenes

def set_winner():

global winner

deltas = [1,2,3]

for x in range(width):

right = x < width - 3

for y in range(height):

upper = y < height - 3

lower = y > 2

if board[x][y] > 0 and \

((upper and 3 == sum(1 for d in deltas if board[x][y] == board[x][y + d])) or \

(right and 3 == sum(1 for d in deltas if board[x][y] == board[x + d][y])) or \

(right and upper and 3 == sum(1 for d in deltas if board[x][y] == board[x + d][y + d])) or \

(right and lower and 3 == sum(1 for d in deltas if board[x][y] == board[x + d][y - d]))):

winner = board[x][y]

def resolve_state():

global state

if state == "Playing":

set_winner()

if winner > 0:

state = "Player" + str(winner) + "Won"

elif width == sum(1 for x in board if sum(1 for y in x if y > 0) == height):

state = "Tie"

# end of file