Answer
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# 11.20 (Game: Connect Four) Connect Four is a two-player board game in which the
# players alternately drop colored disks into a seven-column, six-row vertically
# suspended grid, as shown at cs.armstrong.edu/liang/ConnectFour/ConnectFour.html.
# The objective of the game is to connect four same-colored disks in a row, column,
# or diagonal before your opponent does. The program prompts two players
# to drop a red or yellow disk alternately. Whenever a disk is dropped, the program
# redisplays the board on the console and determines the status of the game
# (win, draw, or continue).
import sys
def dropADisc(player, board):
done = False
while not done:
print("Drop a", "red" if player == 'R' else "yellow", end=" disk at column (0-6): ")
column = eval(input())
if placeADisk(board, column, player):
done = True
else:
print("This column is full. Try a different column")
def placeADisk(board, column, player):
for i in range(len(board)):
if board[i][column] == '\u0000':
board[i][column] = player
return True # successful
return False # full, unsuccessful
def displayBoard(board):
for i in range(len(board) - 1, -1, -1):
print("|", end="")
for j in range(len(board[i])):
print(board[i][j] + "|" if board[i][j] != '\u0000' else " |", end="")
print()
print("----------------------")
def isWon(board):
return isConsecutiveFour(board)
def isDraw(board):
for i in range(len(board)):
for j in range(len(board[i])):
if board[i][j] == '\u0000': return False
return True # All cells are now occupied
def isConsecutiveFour(values):
numberOfRows = len(values)
numberOfColumns = len(values[0])
# Check rows
for i in range(numberOfRows):
if isConsecutiveFourInList(values[i]):
return True
# Check columns
for j in range(numberOfColumns):
column = numberOfRows * [' ']
# Get a column into an array
for i in range(numberOfRows):
column[i] = values[i][j]
if isConsecutiveFourInList(column):
return True
# Check major diagonal (lower part)
for i in range(numberOfRows - 3):
numberOfElementsInDiagonal = min(numberOfRows - i, numberOfColumns)
diagonal = numberOfElementsInDiagonal * [' ']
for k in range(numberOfElementsInDiagonal):
diagonal[k] = values[k + i][k]
if isConsecutiveFourInList(diagonal):
return True
# Check major diagonal (upper part)
for j in range(1, numberOfColumns - 3):
numberOfElementsInDiagonal = min(numberOfColumns - j, numberOfRows)
diagonal = numberOfElementsInDiagonal * [' ']
for k in range(numberOfElementsInDiagonal):
diagonal[k] = values[k][k + j]
if isConsecutiveFourInList(diagonal):
return True
# Check sub-diagonal (left part)
for j in range(3, numberOfColumns):
numberOfElementsInDiagonal = min(j + 1, numberOfRows)
diagonal = numberOfElementsInDiagonal * [' ']
for k in range(numberOfElementsInDiagonal):
diagonal[k] = values[k][j - k]
if isConsecutiveFourInList(diagonal):
return True
# Check sub-diagonal (right part)
for i in range(1, numberOfRows - 3):
numberOfElementsInDiagonal = min(numberOfRows - i, numberOfColumns)
diagonal = numberOfElementsInDiagonal * [' ']
for k in range(numberOfElementsInDiagonal):
diagonal[k] = values[k + i][numberOfColumns - k - 1]
if isConsecutiveFourInList(diagonal):
return True
return False
def isConsecutiveFourInList(values):
for i in range(len(values) - 3):
isEqual = True
for j in range(i, i + 3):
if values[j] == '\u0000' or values[j] != values[j + 1]:
isEqual = False
break
if isEqual: return True
return False
board = []
for i in range(6):
board.append(8 * ["\u0000"])
displayBoard(board)
while True:
# Prompt the first player
dropADisc('R', board)
displayBoard(board)
if isWon(board):
print("The red player won")
sys.exit()
elif isDraw(board):
print("No winner")
sys.exit()
# Prompt the second player
dropADisc('Y', board)
displayBoard(board)
if isWon(board):
print("The yellow player won")
sys.exit()
elif isDraw(board):
print("No winner")
sys.exit()
