多线程-leetcode1114-按序打印

实例-Leetcode并发编程

leetcode-1114 按序打印

leetcode只要 方法1 2 3顺序执行，我对其作了修改，1-2-3-1-2-3循环周期打印
通过两个volatile共享内存变量实现线程间信息交流。
当first和seconde都为false时，first里面的printFirst()才能执行，然后通知printSecond()方法可以执行了。

class Foo {
        void Foo(){
        }
    volatile boolean first = false;
    volatile boolean second = false;
    public void first(Runnable printFirst) throws InterruptedException{
        while (first || second) {

        }
        // printFirst.run() outputs "first". Do not change or remove this line.
        printFirst.run();
        first = true;
    }
    public void second(Runnable printSecond) throws InterruptedException{
        while (!first) {

        }
        // printSecond.run() outputs "second". Do not change or remove this line.
        printSecond.run();
        second = true;
    }
    public void third(Runnable printThird) throws InterruptedException{
        while (!second) {

        }
        // printThird.run() outputs "third". Do not change or remove this line.
        printThird.run();
        first = false;
        second = false;
    }
}