LeetCode - 641 设计循环双端队列（设计）*

class MyCircularDeque {
    
    //底层数组结构
    private int[] deque;
    //头指针
    private int head;
    //尾指针
    private int tail;
    //队列中实际中存放的数的个数
    private int size;
    //队列容量
    private int capacity;
    public MyCircularDeque(int k) {
    
        deque = new int[k];
        head = 0;
        tail = 0;
        size = 0;
        capacity = k;
    }
    
    public boolean insertFront(int value) {
    
        //如果队列已经满了
       if(isFull() == true)
          return false;
       else{
    
           //在头指针指向位置插入value
           deque[head] = value;
           //头指针向前移动
           head = (head -1 + this.capacity) % this.capacity;
           //队列值个数加一
           size += 1;
           return true;
       }
    }
    
    public boolean insertLast(int value) {
    
        //如果队列已经满了
       if(isFull() == true)
          return false;
       else{
    
            //尾指针向后移动
           tail = (tail + 1 + this.capacity) % this.capacity;
           //在尾指针指向位置插入value
           deque[tail] = value;
           //队列值个数加一
           size += 1;
           return true;
       }
    }
    
    public boolean deleteFront() {
    
        //如果队列为空
        if(isEmpty())
          return false;
        else{
    
            head = (head + 1) % this.capacity;
            size -= 1;
            return true;
        }
    }
    
    public boolean deleteLast() {
    
        //如果队列为空
        if(isEmpty())
          return false;
        else{
    
            tail = (tail -1  + this.capacity) % this.capacity;
            size -= 1;
            return true;
        }
    }
    
    public int getFront() {
    
         if(isEmpty())
            return -1;
        else{
    
            int front = (head + 1) % this.capacity;
            return deque[front];
        }
    }
    
    public int getRear() {
    
        if(isEmpty())
            return -1;
        else{
    
            return deque[tail];
        }
    }
    
    public boolean isEmpty() {
    
       return this.size == 0;
    }
    
    public boolean isFull() {
    
        return this.capacity == this.size;
    }
}

/** * Your MyCircularDeque object will be instantiated and called as such: * MyCircularDeque obj = new MyCircularDeque(k); * boolean param_1 = obj.insertFront(value); * boolean param_2 = obj.insertLast(value); * boolean param_3 = obj.deleteFront(); * boolean param_4 = obj.deleteLast(); * int param_5 = obj.getFront(); * int param_6 = obj.getRear(); * boolean param_7 = obj.isEmpty(); * boolean param_8 = obj.isFull(); */