641. Design Circular Deque 

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class MyCircularDeque {

    private final int[] array;
    private int size;
    private int headIndex; // 指向下一个应该插入的头部节点索引
    private int tailIndex; // 指向下一个应该插入的尾部节点索引

    public MyCircularDeque(int k) {
        this.array = new int[k];
        this.tailIndex = (1 + array.length) % array.length;
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

References

641. Design Circular Deque