LeetCode（多线程）- 1114. 按序打印

Posted 2022-02-07 程序员牧码

题目链接：点击打开链接

题目大意：略。

解题思路：略。

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AC 代码

// 解决方案(1)
class Foo 

    public Foo() 
        
    
    volatile int count=1;
    public void first(Runnable printFirst) throws InterruptedException 
        printFirst.run();
        count++;
    

    public void second(Runnable printSecond) throws InterruptedException 
        while (count!=2);
        printSecond.run();
        count++;
    

    public void third(Runnable printThird) throws InterruptedException 
        while (count!=3);
        printThird.run();
    


// 解决方案(2)
class Foo 
    
    private boolean firstFinished;
    private boolean secondFinished;
    private Object lock = new Object();

    public Foo() 
        
    

    public void first(Runnable printFirst) throws InterruptedException 
        
        synchronized (lock) 
            // printFirst.run() outputs "first". Do not change or remove this line.
            printFirst.run();
            firstFinished = true;
            lock.notifyAll(); 
        
    

    public void second(Runnable printSecond) throws InterruptedException 
        
        synchronized (lock) 
            while (!firstFinished) 
                lock.wait();
            
        
            // printSecond.run() outputs "second". Do not change or remove this line.
            printSecond.run();
            secondFinished = true;
            lock.notifyAll();
        
    

    public void third(Runnable printThird) throws InterruptedException 
        
        synchronized (lock) 
           while (!secondFinished) 
                lock.wait();
            

            // printThird.run() outputs "third". Do not change or remove this line.
            printThird.run();