1116.Print-Zero-Even-Odd.java

// https://leetcode.com/problems/print-zero-even-odd/
//
// algorithms
// Medium (45.52%)
// Total Accepted: 198
// Total Submissions: 435
// beats 100.0% of java submissions


import java.util.concurrent.Semaphore;

class ZeroEvenOdd {
    private int n;
    private Semaphore zero = new Semaphore(1);
    private Semaphore even = new Semaphore(0);
    private Semaphore odd = new Semaphore(0);
    
    public ZeroEvenOdd(int n) {
        this.n = n;
    }

    // printNumber.accept(x) outputs "x", where x is an integer.
    public void zero(IntConsumer printNumber) throws InterruptedException {
        for (int i = 0; i < n; i++) {
            zero.acquire();
            printNumber.accept(0);
            if ((i & 1) == 0) {
                odd.release();
            } else {
                even.release();
            }
        }
    }

    public void even(IntConsumer printNumber) throws InterruptedException {
        for (int i = 2; i <= n; i += 2) {
            even.acquire();
            printNumber.accept(i);
            zero.release();
        }
    }

    public void odd(IntConsumer printNumber) throws InterruptedException {
        for (int i = 1; i <= n; i += 2) {
            odd.acquire();
            printNumber.accept(i);
            zero.release();
        }
    }
}