def test_move_head_stay():
tape = Tape('B', ['a', 'b', 'X', 'B'], ['a', 'b'])
tape.move_head('S')
assert tape.get_content() == 'a'
def test_move_head_right_left():
tape = Tape('B', ['a', 'b', 'X', 'B'], ['a', 'b'])
tape.move_head('R')
tape.move_head('L')
assert tape.get_content() == 'a'
import sys
from tape import Direction
from tape import Tape
if __name__ == '__main__':
if len(sys.argv) == 1:
print('usage: {} <palindrome>'.format(sys.argv[0]))
print('where the format of a palindrome is L = { ww^R | w = (0+1)^* }')
sys.exit(0)
tape = Tape(sys.argv[1])
while True:
if tape.read() == '0':
tape.write('x')
tape.move_head(Direction.RIGHT)
if tape.read() in ['0', '1']:
tape.move_head(Direction.RIGHT)
elif tape.read() in ['d', 'x', 'y']:
break
while tape.read() in ['0', '1']:
tape.move_head(Direction.RIGHT)
if tape.read() in ['d', 'x', 'y']:
tape.move_head(Direction.LEFT)
if tape.read() == '0':
tape.write('x')
tape.move_head(Direction.LEFT)
