現(xiàn)有函數(shù)?printNumber?可以用一個(gè)整數(shù)參數(shù)調(diào)用，并輸出該整數(shù)到控制臺(tái)。

• 例如，調(diào)用?printNumber(7)?將會(huì)輸出?7?到控制臺(tái)。

給你類?ZeroEvenOdd?的一個(gè)實(shí)例，該類中有三個(gè)函數(shù)：zero、even?和?odd?。ZeroEvenOdd?的相同實(shí)例將會(huì)傳遞給三個(gè)不同線程：

• 線程 A：調(diào)用?zero()?，只輸出?0
• 線程 B：調(diào)用?even()?，只輸出偶數(shù)
• 線程 C：調(diào)用?odd()?，只輸出奇數(shù)

修改給出的類，以輸出序列?"010203040506..."?，其中序列的長(zhǎng)度必須為?2n?。

實(shí)現(xiàn)?ZeroEvenOdd?類：

• ZeroEvenOdd(int n)?用數(shù)字?n?初始化對(duì)象，表示需要輸出的數(shù)。
• void zero(printNumber)?調(diào)用?printNumber?以輸出一個(gè) 0 。
• void even(printNumber)?調(diào)用printNumber?以輸出偶數(shù)。
• void odd(printNumber)?調(diào)用?printNumber?以輸出奇數(shù)。

示例 1：

輸入：n = 2
輸出："0102"
解釋：三條線程異步執(zhí)行，其中一個(gè)調(diào)用 zero()，另一個(gè)線程調(diào)用 even()，最后一個(gè)線程調(diào)用odd()。正確的輸出為 "0102"。

示例 2：

輸入：n = 5
輸出："0102030405"

1. Semaphore

class ZeroEvenOdd {private int n;private Semaphore zeroSema = new Semaphore(1);private Semaphore oddSema = new Semaphore(0);//奇數(shù)private Semaphore evenSema = new Semaphore(0);//偶數(shù)public ZeroEvenOdd(int n) {this.n = n;}public void zero(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {zeroSema.acquire();printNumber.accept(0);if (i % 2!= 0) {//奇數(shù)oddSema.release();} else {evenSema.release();}}}public void even(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2== 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程evenSema.acquire();printNumber.accept(i);zeroSema.release();}}}public void odd(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2 != 0) {//奇數(shù)，打印奇數(shù)，并釋放zero的線程oddSema.acquire();printNumber.accept(i);zeroSema.release();}}}
}

2.?synchronized

class ZeroEvenOdd {private int n;private final Object ob=new Object();private volatile int flag=0;public ZeroEvenOdd(int n) {this.n = n;}public void zero(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {synchronized (ob){while (flag!=0){ob.wait();}printNumber.accept(0);if(i%2==0)flag=2;elseflag=1;ob.notifyAll();}}}public void even(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2== 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程synchronized (ob){while (flag!=2){ob.wait();}printNumber.accept(i);flag=0;ob.notifyAll();}}}}public void odd(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2!= 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程synchronized (ob){while (flag!=1){ob.wait();}printNumber.accept(i);flag=0;ob.notifyAll();}}}}
}

3. CountDownLatch

class ZeroEvenOdd {private int n;private CountDownLatch countDownLatch_zero=new CountDownLatch(0);private CountDownLatch countDownLatch_even=new CountDownLatch(1);private CountDownLatch countDownLatch_odd=new CountDownLatch(1);public ZeroEvenOdd(int n) {this.n = n;}public void zero(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {countDownLatch_zero.await();printNumber.accept(0);countDownLatch_zero=new CountDownLatch(1);if (i % 2!= 0) {//奇數(shù)countDownLatch_odd.countDown();} else {countDownLatch_even.countDown();}}}public void even(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2== 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程countDownLatch_even.await();printNumber.accept(i);countDownLatch_even=new CountDownLatch(1);countDownLatch_zero.countDown();}}}public void odd(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2 != 0) {//奇數(shù)，打印奇數(shù)，并釋放zero的線程countDownLatch_odd.await();printNumber.accept(i);countDownLatch_odd=new CountDownLatch(1);countDownLatch_zero.countDown();}}}
}

4. Lock

class ZeroEvenOdd {private int n;private volatile int flag=0;Lock lock=new ReentrantLock();Condition condition_zero = lock.newCondition();Condition conditon_even = lock.newCondition();Condition condition_odd = lock.newCondition();public ZeroEvenOdd(int n) {this.n = n;}public void zero(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {lock.lock();try{while (flag!=0){condition_zero.await();}printNumber.accept(0);if(i%2==0) {flag = 2;conditon_even.signal();}else {flag = 1;condition_odd.signal();}}finally {lock.unlock();}}}public void even(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2== 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程lock.lock();try {while (flag != 2) {conditon_even.await();}printNumber.accept(i);flag = 0;condition_zero.signal();}finally {lock.unlock();}}}}public void odd(IntConsumer printNumber) throws InterruptedException {for (int i = 1; i <= n; i++) {if (i % 2!= 0) {//偶數(shù) 打印偶數(shù) 并釋放zero的線程lock.lock();try {while (flag != 1) {condition_odd.await();}printNumber.accept(i);flag = 0;condition_zero.signal();}finally {lock.unlock();}}}}
}