designCircularDeque.cpp

// Source: https://leetcode.com/problems/design-circular-deque/
// Author: Miao Zhang
// Date:   2021-02-26

class MyCircularDeque {
public:
    /** Initialize your data structure here. Set the size of the deque to be k. */
    MyCircularDeque(int k) : capacity_(k), q_(k), head_(1), tail_(-1), size_(0) {

    }

    /** Adds an item at the front of Deque. Return true if the operation is successful. */
    bool insertFront(int value) {
        if (isFull()) return false;
        head_ = (head_ - 1 + capacity_) % capacity_;
        q_[head_] = value;
        if (size_ == 0) tail_ = head_;
        size_++;
        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;
        tail_ = (tail_ + 1 + capacity_) % capacity_;
        q_[tail_] = value;
        if (size_ == 0) head_ = tail_;
        size_++;
        return true;
    }

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

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

    /** Get the front item from the deque. */
    int getFront() {
        if (isEmpty()) return -1;
        return q_[head_];
    }

    /** Get the last item from the deque. */
    int getRear() {
        if (isEmpty()) return -1;
        return q_[tail_];
    }

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

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

private:
    const int capacity_;
    int head_;
    int tail_;
    int size_;
    vector<int> q_;
};

/**
 * 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();
 */