1279. Traffic Light Controlled Intersection - cocoder39/coco39_LC GitHub Wiki

1279. Traffic Light Controlled Intersection

from threading import Lock

class TrafficLight:
    def __init__(self):
        self.green = 1
        self.lock = Lock()

    def carArrived(
        self,
        carId: int,                      # ID of the car
        roadId: int,                     # ID of the road the car travels on. Can be 1 (road A) or 2 (road B)
        direction: int,                  # Direction of the car
        turnGreen: 'Callable[[], None]', # Use turnGreen() to turn light to green on current road
        crossCar: 'Callable[[], None]'   # Use crossCar() to make car cross the intersection
    ) -> None:
        with self.lock:
            if roadId != self.green:
                turnGreen()
                self.green = roadId
            crossCar()

def foo():
    with lock:
        # only one thread can execute code there

==

def foo():
    lock.acquire()
    try:
        # only one thread can execute code there
    finally:
        lock.release() #release lock