Leetcode 641: Design Circular Deque

https://leetcode.com/problems/design-circular-deque/description/

Notes:

This question is similar to another design question Leetcode 622: Design Circular Queue.

Please see the code below:

class MyCircularDeque {
private:
    vector<int> buffer;
    int len;
    int front;
    int rear;
    int ct;

public:
    /** Initialize your data structure here. Set the size of the deque to be k. */
    MyCircularDeque(int k): buffer(k, 0), len(k), front(k-1), rear(0), ct(0) {

    }

    /** Adds an item at the front of Deque. Return true if the operation is successful. */
    bool insertFront(int value) {
        if(isFull()) return false;
        buffer[front] = value;
        front = (front - 1 + len)%len;
        ++ct;
        return true;
    }

    /** Adds an item at the rear of Deque. Return true if the operation is successful. */
    bool insertLast(int value) {
        if(isFull()) return false;
        buffer[rear] = value;
        rear = (rear + 1)%len;
        ++ct;
        return true;
    }

    /** Deletes an item from the front of Deque. Return true if the operation is successful. */
    bool deleteFront() {
        if(isEmpty()) return false;
        front = (front + 1)%len;
        --ct;
        return true;
    }

    /** Deletes an item from the rear of Deque. Return true if the operation is successful. */
    bool deleteLast() {
        if(isEmpty()) return false;
        rear = (rear - 1 + len)%len;
        --ct;
        return true;
    }
   
    /** Get the front item from the deque. */
    int getFront() {
        if(isEmpty()) return -1;
        return buffer[(front+1)%len];
    }

    /** Get the last item from the deque. */
    int getRear() {
        if(isEmpty()) return -1;
        return buffer[(rear-1+len)%len];
    }

    /** Checks whether the circular deque is empty or not. */
    bool isEmpty() {
        return ct == 0;
    }

    /** Checks whether the circular deque is full or not. */
    bool isFull() {
        return ct == len;
    }
};

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