/**
1. 设计思路:
1.1 两个指针, head 为当前队列头, tail为当前队列尾的下一个位置
1.2 每次取+1模

2. testcase:
容量: 0, 1, 2, 3

3. 这个写法为什么 size = k + 1, 极限当k = 1 时, 此时head == tail == 0, 
这时对应的意义为, head 为队列头, tail为队列尾部下一个位置, 即左闭右开, 然而( tail + 1 ) % size 仍然为1 ,无法判断, 所以空出一位
也就是说 tail 应该一直指向 "空"位置, 所以 要多开一个空间


4. 如果要空间恰好为k, 可以使用统计队列元素的方法, 此时 tail = (head + count - 1) % size;

*/


class MyCircularQueue {

    /** Initialize your data structure here. Set the size of the queue to be k. */
    int head, tail, size;
    int[] data;
    public MyCircularQueue(int k) {
        this.size = k;
        this.head = 0;
        this.tail = 0;
        this.data = new int[k];
    }

    /** Insert an element into the circular queue. Return true if the operation is successful. */
    public boolean enQueue(int value) {
       if (isFull()) return false;
       tail = isEmpty() ? tail: (tail + 1) % size;
       data[tail] = value;
       count++;
       return true;
    }

    /** Delete an element from the circular queue. Return true if the operation is successful. */
    public boolean deQueue() {
        if (isEmpty()) return false;
        count --;
        head = (head + 1) % size;
        return true;
    }

    /** Get the front item from the queue. */
    public int Front() {
        return isEmpty() ? -1 : data[head];
    }

    /** Get the last item from the queue. */
    public int Rear() {
        return isEmpty() ? -1 : data[tail];
    }

    /** Checks whether the circular queue is empty or not. */
    public boolean isEmpty() {
        return count == 0;
    }

    /** Checks whether the circular queue is full or not. */
    public boolean isFull() {
        return count == size;
    }
}

class MyCircularQueue {

    /** Initialize your data structure here. Set the size of the queue to be k. */
    int head, size, count;
    int[] data;
    public MyCircularQueue(int k) {
        this.size = k;
        this.head = 0;
        this.count = 0;
        this.data = new int[k];
    }
        private int getTailIndex(){
        return (head + count - 1) % size;
    }

    /** Insert an element into the circular queue. Return true if the operation is successful. */
    public boolean enQueue(int value) {
       if (isFull()) return false;
       count++;
       data[getTailIndex()] = value;
       return true;
    }

    /** Delete an element from the circular queue. Return true if the operation is successful. */
    public boolean deQueue() {
        if (isEmpty()) return false;
        count --;
        head = (head + 1) % size;
        return true;
    }

    /** Get the front item from the queue. */
    public int Front() {
        return isEmpty() ? -1 : data[head];
    }

    /** Get the last item from the queue. */
    public int Rear() {
        return isEmpty() ? -1 : data[getTailIndex()];
    }

    /** Checks whether the circular queue is empty or not. */
    public boolean isEmpty() {
        return count == 0;
    }

    /** Checks whether the circular queue is full or not. */
    public boolean isFull() {
        return count == size;
    }
}