How hard is LeetCode 1279. Traffic Light Controlled Intersection?

LeetCode 1279. Traffic Light Controlled Intersection is rated Easy on LeetCode.

What topics does LeetCode 1279. Traffic Light Controlled Intersection cover?

LeetCode 1279. Traffic Light Controlled Intersection is tagged Concurrency on LeetCode.

Is LeetCode 1279. Traffic Light Controlled Intersection a premium problem?

Yes. LeetCode 1279. Traffic Light Controlled Intersection is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.

Traffic Light Controlled Intersection — LeetCode 1279 Python Solution

EasyLeetCode PremiumConcurrency

Problem: #1279
Reading time: 5 min
Source: leetcode.com

The problem

There is an intersection of two roads. First road is road A where cars travel from North to South in direction 1 and from South to North in direction 2.

Example

Input: cars = [1,3,5,2,4], directions = [2,1,2,4,3], arrivalTimes = [10,20,30,40,50]
Output: [

Python solution

Python

from threading import Lock


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

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

Complexity

Measure	Complexity
Time	O(n)
Space	O(1) to O(n) auxiliary

Frequently asked questions

How hard is LeetCode 1279. Traffic Light Controlled Intersection?: LeetCode 1279. Traffic Light Controlled Intersection is rated Easy on LeetCode.
What topics does LeetCode 1279. Traffic Light Controlled Intersection cover?: LeetCode 1279. Traffic Light Controlled Intersection is tagged Concurrency on LeetCode.
Is LeetCode 1279. Traffic Light Controlled Intersection a premium problem?: Yes. LeetCode 1279. Traffic Light Controlled Intersection is a LeetCode Premium problem, so the full statement and test cases require a paid LeetCode subscription.