printinOrder.py

#! /usr/bin/env python3
# -*- coding: utf-8 -*-

# Source: https://leetcode.com/problems/print-in-order/
# Author: Miao Zhang
# Date:   2021-04-12

from threading import Lock
class Foo:
    def __init__(self):
        self.lock1 = Lock()
        self.lock2 = Lock()
        self.lock1.acquire()
        self.lock2.acquire()

    def first(self, printFirst: 'Callable[[], None]') -> None:
        
        # printFirst() outputs "first". Do not change or remove this line.
        printFirst()
        self.lock1.release()

    def second(self, printSecond: 'Callable[[], None]') -> None:
        
        # printSecond() outputs "second". Do not change or remove this line.
        with self.lock1:
            printSecond()
            self.lock2.release()

    def third(self, printThird: 'Callable[[], None]') -> None:
        
        # printThird() outputs "third". Do not change or remove this line.
        with self.lock2:
            printThird()