MidpointKarel.py

from karel.stanfordkarel import *

"""
File: MidpointKarel.py
----------------------
When you finish writing it, MidpointKarel should
leave a beeper on the corner closest to the center of 1st Street
(or either of the two central corners if 1st Street has an even
number of corners).  Karel can put down additional beepers as it
looks for the midpoint, but must pick them up again before it
stops.  The world may be of any size, but you are allowed to
assume that it is at least as tall as it is wide.
"""


def main():
    # make main diagonal
    draw_diagonal(MAGENTA)
    # drop back down
    move_to_bottom()
    # face west
    turn_right()
    # scan diagonal for magenta
    while not corner_color_is(MAGENTA):
        continue_on_diagonal()
    # we found the magenta!
    drop_bottom_beeper()
    # back to the beginning
    turn_right()
    move_forward_full()
    turn_around()
    # clean up diagonal
    draw_diagonal(BLANK)
    # get back to the beeper
    find_beeper()

def continue_on_diagonal():
    move()
    if facing_west():
        turn_right()
    else:
        turn_left()

def turn_right():
    turn_left()
    turn_left()
    turn_left()

def turn_around():
    turn_left()
    turn_left()

def move_to_bottom():
    if facing_north():
        turn_around()
    elif facing_east():
        turn_right()
    elif facing_west():
        turn_left()
    move_forward_full()

def drop_bottom_beeper():
    move_to_bottom()
    put_beeper()

def move_forward_full():
    while front_is_clear():
        move()

def draw_diagonal(color):
    while front_is_clear():
        paint_corner(color)
        move()
        turn_left()
        if front_is_clear():
            move()
            turn_right()
        else:
            turn_right()
    paint_corner(color)

def find_beeper():
    turn_right()
    move_forward_full()
    turn_right()
    while no_beepers_present():
        move()


# There is no need to edit code beyond this point

if __name__ == "__main__":
    run_karel_program()

MidpointPingPong.py

from karel.stanfordkarel import *

def main():
    put_beeper()
    line()
    wall()
    while front_is_clear():
        while no_beepers_present():
            move()
        pick_beeper()
        go()
        wall()

def line():
    while front_is_clear():
        move()
        put_beeper()

def wall():
    if front_is_blocked():
        turn_around()

def go():
    while front_is_clear():
        move()

def turn_right():
    "turns Karel right"
    for i in range(3):
        turn_left()

def turn_around():
    "turns Karel 180 degrees"
    for i in range(2):
        turn_left()

if __name__ == "__main__":
    run_karel_program()