622. Design Circular Queue 

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class MyCircularQueue {

    private final int[] array;
    private int headIndex;
    private int tailIndex; // 即将插入元素的索引
    private int size;

    public MyCircularQueue(int k) {
        this.array = new int[k];
        this.headIndex = this.tailIndex = 0;
        this.size = 0;
    }

    public boolean enQueue(int value) {
        if (isFull()) {
            return false;
        }

        array[tailIndex] = value;
        size++;
        tailIndex = (tailIndex + 1) % array.length;
        return true;
    }

    public boolean deQueue() {
        if (isEmpty()) {
            return false;
        }

        size--;
        headIndex = (headIndex + 1) % array.length;
        return true;
    }

    public int Front() {
        if (isEmpty()) {
            return -1;
        }

        return array[headIndex];
    }

    public int Rear() {
        if (size == 0) {
            return -1;
        }

        return array[(tailIndex - 1 + array.length) % array.length];
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public boolean isFull() {
        return size == array.length;
    }
}

References

622. Design Circular Queue