def walk(instructions):
"""
>>> walk("R2, L3")
(5, None)
>>> walk("R2, R2, R2")
(2, None)
>>> walk("R5, L5, R5, R3")
(12, None)
>>> walk("R8, R4, R4, R8")
(8, 4)
"""
position = BlockCoord(0, 0)
heading = Coord(0, 1)
visited = set((position, ))
part2 = None
for instruction in instructions.strip().split(', '):
if instruction[0] == 'R':
heading = heading.rotate_right()
elif instruction[0] == 'L':
heading = heading.rotate_left()
for step in range(int(instruction[1:])):
position += heading
if part2 is None and position in visited:
part2 = position
visited.add(position)
return (position.distance_blocks(),
part2.distance_blocks() if part2 else None)
def paint(program, start):
hull = defaultdict(int)
position = Coord(0, 0)
direction = Coord(0, 1)
computer = Computer(program)
computer._input = []
hull[position] = start
while not computer.halted:
try:
computer.add_input(hull[position])
hull[position] = computer.run()
turn = computer.run()
if turn == 0:
direction = direction.rotate_left()
else:
direction = direction.rotate_right()
position = position + direction
except Halted:
return hull
