ImplementCircularQueue.cpp

#include <vector>
#include <iostream>

using namespace std;

class MyCircularDeque {
private:
    vector<int> buffer;
    int cnt;
    int k;
    int front;
    int rear;
public:
    /** Initialize your data structure here. Set the size of the deque to be k. */
    MyCircularDeque(int k): buffer(k, 0), cnt(0), k(k), front(k - 1), rear(0) {
    }
    
    /** Adds an item at the front of Deque. Return true if the operation is successful. */
    bool insertFront(int value) {
        if (cnt == k) {
            return false;
        }
        buffer[front] = value;
        front = (front - 1 + k) % k;
        ++cnt;

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

        return true;
    }
    
    /** Deletes an item from the front of Deque. Return true if the operation is successful. */
    bool deleteFront() {
        if (cnt == 0) {
            return false;
        }
        front = (front + 1) % k;
        --cnt;

        return true;
    }
    
    /** Deletes an item from the rear of Deque. Return true if the operation is successful. */
    bool deleteLast() {
        if (cnt == 0) {
            return false;
        }
        rear = (rear - 1 + k) % k;
        --cnt;

        return true;
    }
    
    /** Get the front item from the deque. */
    int getFront() {
        if (cnt == 0) {
            return -1;
        }
        return buffer[(front + 1) % k];
    }
    
    /** Get the last item from the deque. */
    int getRear() {
        if (cnt == 0) {
            return -1;
        }
        return buffer[(rear - 1 + k) % k];
    }
    
    /** Checks whether the circular deque is empty or not. */
    bool isEmpty() {
        return cnt == 0;
    }
    
    /** Checks whether the circular deque is full or not. */
    bool isFull() {
        return cnt == k;
    }
};