CS Bridge | UN Karel (with solution)

Handouts: Karel Reference
File: un_karel.py

Karel has been hired by the UN to come and help build houses. The day needs saving and Karel is clearly the best robot for the job. Your goal is to have Karel walk along the bottom row and build a house like the following every time Karel finds a beeper:

The below images show what Karel should do for two example worlds. You can assume that no houses will overlap and that all houses will fit inside the world. You can't assume the size of the world or the number of houses!

from karel.stanfordkarel import *

"""
File: un_karel.py
------------------------
This program makes Karel builds houses, as work for the UN.  Karel will
build a house on each spot marked by a beeper in the bottom row
of the world.
"""


def main():
    while front_is_clear():
        move()
        if beepers_present():
            build_house()


def build_house():
    """
    Constructs a single house centered around Karel's current position.
    Assumes that there is a beeper present at that location.
    At the end of the function, Karel will be facing east on the bottom-
    right corner of the house, one square to the east of Karel's original
    position.
    """

    # Build the left column of the house first
    pick_beeper()
    turn_around()
    move()
    turn_right()
    place_three()

    # Build the middle column of the house second
    turn_right()
    move()
    turn_right()
    place_three()

    # Build the right column of the house last
    turn_left()
    move()
    turn_left()
    place_three()
    turn_around()
    move_to_wall()
    turn_left()


def move_to_wall():
    """
    Move forward until Karel hits a wall.
    """
    while front_is_clear():
        move()


def place_three():
    """
    Places three beepers in a row and moves three times!  Assumes
    that there is enough space in front of Karel to move 3 times.
    After this function executes, Karel will be 3 spaces further
    in the direction it is facing, immediately after the last square
    where it put down a beeper.
    """
    for i in range(3):
        put_beeper()
        move()


def turn_around():
    """
    Karel turns 180 degrees - e.g. if Karel is facing east, now Karel will
    face west.  If Karel is facing north, Karel will now face south.
    """
    turn_left()
    turn_left()


def turn_right():
    """
    Karel turns right - e.g. if Karel is facing east, now Karel will face
    south.  If Karel is facing north, Karel will now face east.
    """
    for i in range(3):
        turn_left()


# There is no need to edit code beyond this point

if __name__ == "__main__":
    run_karel_program()

UN Karel (with solution)

Solution