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print-in-order.py
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print-in-order.py
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""" The simple stupid slowest way
using shared variables as semaphores
class Foo:
def __init__(self):
self.second_sema = False
self.third_sema = False
pass
def first(self, printFirst: 'Callable[[], None]') -> None:
# printFirst() outputs "first". Do not change or remove this line.
printFirst()
self.second_sema = True
def second(self, printSecond: 'Callable[[], None]') -> None:
while not self.second_sema:
pass
# printSecond() outputs "second". Do not change or remove this line.
printSecond()
self.third_sema = True
def third(self, printThird: 'Callable[[], None]') -> None:
while not self.third_sema:
pass
# printThird() outputs "third". Do not change or remove this line.
printThird()
"""
from threading import Lock
class Foo:
""" This solution uses thread locks (threading.Lock)
40ms / 14MB / Accepted
"""
def __init__(self):
self.second_locs = Lock()
self.third_lock = Lock()
self.second_locs.acquire()
self.third_lock.acquire()
pass
def first(self, printFirst: 'Callable[[], None]') -> None:
# printFirst() outputs "first". Do not change or remove this line.
printFirst()
self.second_locs.release()
def second(self, printSecond: 'Callable[[], None]') -> None:
self.second_locs.acquire()
# printSecond() outputs "second". Do not change or remove this line.
printSecond()
self.third_lock.release()
def third(self, printThird: 'Callable[[], None]') -> None:
self.third_lock.acquire()
# printThird() outputs "third". Do not change or remove this line.
printThird()