Leetcode 622: Design Circular Queue

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

Notes:

This is a good design question. It seems boring, but actually can test some data structure capability.

This question is similar to another question: Leetcode 641 Design Circular Deque.

See the code below:

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

public:
    /** Initialize your data structure here. Set the size of the queue to be k. */
    MyCircularQueue(int k): buffer(k, 0), front(0), rear(0), len(k), ct(0) {
    }
   
    /** Insert an element into the circular queue. Return true if the operation is successful. */
    bool enQueue(int value) {
        if(isFull()) return false;
        buffer[rear] = value;
        rear = (rear + 1)%len;
        ++ct;
        return true;
    }

    /** Delete an element from the circular queue. Return true if the operation is successful. */
    bool deQueue() {
        if(isEmpty()) return false;
        front = (front + 1)%len;
        --ct;
        return true;
    }

    /** Get the front item from the queue. */
    int Front() {
        if(isEmpty()) return -1;
        return buffer[front];
    }

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

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

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

/**
 * Your MyCircularQueue object will be instantiated and called as such:
 * MyCircularQueue* obj = new MyCircularQueue(k);
 * bool param_1 = obj->enQueue(value);
 * bool param_2 = obj->deQueue();
 * int param_3 = obj->Front();
 * int param_4 = obj->Rear();
 * bool param_5 = obj->isEmpty();
 * bool param_6 = obj->isFull();
 */