TicTacToe.py

# Perfect TicTacToe AI, will never lose, programmed by Jordan Oberstein.

import random

X = "X"  # define X
O = "O"  # define O
empty = " "  # define an empty space
S = [" "] * 9  # array of 9 spaces
turn = 1  # turn counter


def print_instructions():  # prints instructions
    print "This is a game of Tic Tac Toe, the computer will never lose."
    print "Fill in spaces on the board according to the board printed below.\n"
    print "  1 | 2 | 3"
    print " ", "-" * 9
    print "  4 | 5 | 6"
    print " ", "-" * 9
    print "  7 | 8 | 9\n"
    print "If you get 3 of your leters in a row (horizontally, vertically, or diagonally), then you win!"
    print "Good luck!\n"


def print_board():  # prints board
    print "\n ", S[0], "|", S[1], "|", S[2]
    print " ", "-" * 9
    print " ", S[3], "|", S[4], "|", S[5]
    print " ", "-" * 9
    print " ", S[6], "|", S[7], "|", S[8], "\n"


def assign_winconditions():  # array of win conditions
    global WinConditions
    WinConditions = [
        (S[0], S[1], S[2]),  # row1
        (S[3], S[4], S[5]),  # row2
        (S[6], S[7], S[8]),  # row3
        (S[0], S[3], S[6]),  # col1
        (S[1], S[4], S[7]),  # col2
        (S[2], S[5], S[8]),  # col3
        (S[0], S[4], S[8]),  # dia1
        (S[2], S[4], S[6])  # dia2
    ]


def assign_letter():  # assigns chosen letter to player
    global player, cpu
    cpu = empty
    player = raw_input("What letter would you like to be: ")
    while not (player == 'X' or player == 'O' or player == 'x' or player == 'o'):
        player = raw_input("What letter would you like to be: ")
    if player == X or player == 'x':
        player = X
        cpu = O
    if player == O or player == 'o':
        player = O
        cpu = X


def assign_order():  # randomly chooses order of turns
    global order
    choice = random.choice('XO')
    print choice + " will go first"
    if choice == X:
        order = [X, O, X, O, X, O, X, O, X]
    if choice == O:
        order = [O, X, O, X, O, X, O, X, O]
    print order, "is the order."
    print player + " is the player."
    print cpu + " is the cpu."
    order.insert(0, empty)  # compesnate for turn = 1, make order index start at 1


def check_win():  # checks if there is winner
    global winner
    winner = empty
    for i in range(8):
        if WinConditions[i] == (X, X, X):
            winner = X
            print winner + " wins using WinCondition", WinConditions[i], "index", i
        if WinConditions[i] == (O, O, O):
            winner = O
            print winner + " wins using WinCondition", WinConditions[i], "index", i
        i += 1


def player_move(turn):  # function for player's move
    moveP = raw_input("Choose a Space from 1-9 for " + player + " to Move: ")
    while not moveP.isdigit() or int(moveP) not in range(1, 10) or S[int(moveP) - 1] is not empty:
        moveP = raw_input("Choose a Space from 1-9 for " + player + " to Go: ")
    S[int(moveP) - 1] = order[turn]
    print "The Player has gone on space", moveP, "index", int(moveP) - 1


def cpu_win():  # checks if cpu can win
    global movelist
    if WinConditions[0] == (empty, cpu, cpu) or WinConditions[3] == (empty, cpu, cpu) or WinConditions[6] == (empty, cpu, cpu):
        movelist.append(0)
    if WinConditions[0] == (cpu, empty, cpu) or WinConditions[4] == (empty, cpu, cpu):
        movelist.append(1)
    if WinConditions[0] == (cpu, cpu, empty) or WinConditions[5] == (empty, cpu, cpu) or WinConditions[7] == (empty, cpu, cpu):
        movelist.append(2)
    if WinConditions[1] == (empty, cpu, cpu) or WinConditions[3] == (cpu, empty, cpu):
        movelist.append(3)
    if WinConditions[1] == (cpu, empty, cpu) or WinConditions[4] == (cpu, empty, cpu) or WinConditions[6] == (cpu, empty, cpu) or WinConditions[7] == (cpu, empty, cpu):
        movelist.append(4)
    if WinConditions[1] == (cpu, cpu, empty) or WinConditions[5] == (cpu, empty, cpu):
        movelist.append(5)
    if WinConditions[2] == (empty, cpu, cpu) or WinConditions[3] == (cpu, cpu, empty) or WinConditions[7] == (cpu, cpu, empty):
        movelist.append(6)
    if WinConditions[2] == (cpu, empty, cpu) or WinConditions[4] == (cpu, cpu, empty):
        movelist.append(7)
    if WinConditions[2] == (cpu, cpu, empty) or WinConditions[5] == (cpu, cpu, empty) or WinConditions[6] == (cpu, cpu, empty):
        movelist.append(8)


def cpu_block():  # checks if player can win
    global movelist
    if WinConditions[0] == (empty, player, player) or WinConditions[3] == (empty, player, player) or WinConditions[6] == (empty, player, player):
        movelist.append(0)
    if WinConditions[0] == (player, empty, player) or WinConditions[4] == (empty, player, player):
        movelist.append(1)
    if WinConditions[0] == (player, player, empty) or WinConditions[5] == (empty, player, player) or WinConditions[7] == (empty, player, player):
        movelist.append(2)
    if WinConditions[1] == (empty, player, player) or WinConditions[3] == (player, empty, player):
        movelist.append(3)
    if WinConditions[1] == (player, empty, player) or WinConditions[4] == (player, empty, player) or WinConditions[6] == (player, empty, player) or WinConditions[7] == (player, empty, player):
        movelist.append(4)
    if WinConditions[1] == (player, player, empty) or WinConditions[5] == (player, empty, player):
        movelist.append(5)
    if WinConditions[2] == (empty, player, player) or WinConditions[3] == (player, player, empty) or WinConditions[7] == (player, player, empty):
        movelist.append(6)
    if WinConditions[2] == (player, empty, player) or WinConditions[4] == (player, player, empty):
        movelist.append(7)
    if WinConditions[2] == (player, player, empty) or WinConditions[5] == (player, player, empty) or WinConditions[6] == (player, player, empty):
        movelist.append(8)


def cpu_move_turn_one(turn):  # cpu move for turn 1, corner
    moveC = random.randrange(0, 9, 2)
    while (S[moveC] != empty) or moveC == 4:
        moveC = random.randrange(0, 9, 2)
    print moveC, "is random intiger"
    S[moveC] = order[turn]
    print "The Computer will go on space", moveC + 1, "index", moveC


def cpu_move_turn_two(turn):  # cpu move for turn 2, center, if no center than corner
    moveC = 4
    while S[moveC] is not empty:
        moveC = random.randrange(0, 9, 2)
    print moveC, "is random intiger"
    S[moveC] = order[turn]
    print "The Computer will go on space", moveC + 1, "index", moveC


def cpu_move_turn_three(turn):  # cpu move for turn 3
    if S[1] == player or S[3] == player or S[5] == player or S[7] == player:  # if player is edge, cpu moves in center
        S[4] = order[turn]
        print "The Computer will go on space 5 index 4"
    if S[0] == player or S[2] == player or S[6] == player or S[8] == player:  # if player is corner, cpu moves in corner (opposite to cpu if possible)
        placeholder = False # variable to prevent if statement conditions from being true multiple times in loop
        for moveC in range(0, 9, 2):
            if S[moveC] == cpu and placeholder == False:
                if S[8 - moveC] == empty:
                    S[8 - moveC] = order[turn]
                    print "The Computer will go on space", 9 - moveC, "index", 8 - moveC
                    placeholder = True
                if S[8 - moveC] == player:
                    moveC = random.randrange(0, 9, 2)
                    while (S[moveC] != empty) or moveC == 4:
                        moveC = random.randrange(0, 9, 2)
                    S[moveC] = order[turn]
                    print "The Computer will go on space", moveC + 1, "index", moveC
                    placeholder = True
    if S[4] == player:  # if player is center, cpu moves in opposite corner
        for moveC in range(0, 9, 2):
            if S[moveC] == cpu and S[8 - moveC] == empty:  # code block can only run once
                S[8 - moveC] = order[turn]
                print "The Computer will go on space", 9 - moveC, "index", 8 - moveC


def cpu_move_turn_four(turn):  # cpu move for turn 4
    # player plays corner, cpu plays center, player plays opposite edge (to player)
    # player plays edge, cpu plays center, player plays opposite corner (to player)
    # player plays edge, cpu plays center, player plays adjacent edge (to player)
    if player == S[4]:
        if (S[0] == player and S[8] == cpu) or (S[2] == player and S[6] == cpu) or (S[6] == player and S[2] == cpu) or (S[8] == player and S[0] == cpu):  
        # player is center and corner, cpu is opposite corner
            moveC = random.randrange(0, 9, 2)
            while (S[moveC] != empty) or moveC == 4:
                moveC = random.randrange(0, 9, 2)
            S[moveC] = order[turn]  # plays on corner
            print "The Computer will go on space", moveC + 1, "index", moveC
        else:
            cpu_move(turn)
    elif cpu == S[4]:
        if ((S[0] and S[8]) == player or (S[2] and S[6]) == player):  # cpu is center, player is 2 opposite corners
            moveC = random.randrange(1, 8, 2)
            while S[moveC] is not empty:
                moveC = random.randrange(1, 8, 2)
            S[moveC] = order[turn]  # plays on edge
            print "The Computer will go on space", moveC + 1, "index", moveC
        elif ((S[1] and S[7]) == player or (S[3] and S[5]) == player):  # cpu is center, player is 2 opposite edges
            moveC = random.randrange(0, 9, 2)
            while (S[moveC] != empty) or moveC == 4:
                moveC = random.randrange(0, 9, 2)
            S[moveC] = order[turn]  # plays on corner
            print "The Computer will go on space", moveC + 1, "index", moveC
        else:
            cpu_move(turn)
    else:
        cpu_move(turn)


def cpu_move_turn_five(turn):
    # cpu plays corner, player plays adjacent edge, cpu plays center, player plays opposite corner (to cpu)
    # cpu plays corner, player plays opposite corner, cpu plays adjacent corner, plays edge blocking cpu
    cpu_move(turn)


def cpu_move(turn):  # cpu move for turns > 2
    global movelist
    movelist = []  # list of moves, optimal move inserted at start
    randommoveC = random.randint(0, 8)
    while S[randommoveC] is not empty:
        randommoveC = random.randint(0, 8)
    cpu_win()
    print "After cpu_win", movelist
    cpu_block()
    print "After cpu_block", movelist
    movelist.append(randommoveC)
    print "after random number", movelist
    moveC = movelist[0]
    S[int(moveC)] = order[turn]
    print "The Computer will go on space", int(moveC) + 1, "index", moveC


def main(turn):  # combines function into complete game
    print_instructions()
    assign_letter()
    assign_order()
    print_board()
    assign_winconditions()
    while turn < 10:  # gameplay runs in this loop
        print "turn:", turn
        if order[turn] == player:
            player_move(turn)
        if order[turn] == cpu:
            if turn == 1:
                cpu_move_turn_one(turn)
            elif turn == 2:
                cpu_move_turn_two(turn)
            elif turn == 3:
                cpu_move_turn_three(turn)
            elif turn == 4:
                cpu_move_turn_four(turn)
            elif turn == 5:
                cpu_move_turn_five(turn)
            else:
                cpu_move(turn)
        print_board()
        assign_winconditions()
        check_win()
        turn += 1
        if winner is not empty:
            turn = 10
            print winner + " Is tne Winner!\n"
        if winner is empty and turn == 10:
            print "The Game Is a Tie.\n"

main(turn)