641. Design Circular Deque

Medium (Trung bình) C++ 🔗 Xem trên LeetCode

📋 Đề Bài

Design your implementation of the circular double-ended queue (deque).

Implement the MyCircularDeque class:

  • MyCircularDeque(int k) Initializes the deque with a maximum size of k.
  • boolean insertFront() Adds an item at the front of Deque. Returns true if the operation is successful, or false otherwise.
  • boolean insertLast() Adds an item at the rear of Deque. Returns true if the operation is successful, or false otherwise.
  • boolean deleteFront() Deletes an item from the front of Deque. Returns true if the operation is successful, or false otherwise.
  • boolean deleteLast() Deletes an item from the rear of Deque. Returns true if the operation is successful, or false otherwise.
  • int getFront() Returns the front item from the Deque. Returns -1 if the deque is empty.
  • int getRear() Returns the last item from Deque. Returns -1 if the deque is empty.
  • boolean isEmpty() Returns true if the deque is empty, or false otherwise.
  • boolean isFull() Returns true if the deque is full, or false otherwise.

 

Example 1:

Input
["MyCircularDeque", "insertLast", "insertLast", "insertFront", "insertFront", "getRear", "isFull", "deleteLast", "insertFront", "getFront"]
[[3], [1], [2], [3], [4], [], [], [], [4], []]
Output
[null, true, true, true, false, 2, true, true, true, 4]

Explanation
MyCircularDeque myCircularDeque = new MyCircularDeque(3);
myCircularDeque.insertLast(1);  // return True
myCircularDeque.insertLast(2);  // return True
myCircularDeque.insertFront(3); // return True
myCircularDeque.insertFront(4); // return False, the queue is full.
myCircularDeque.getRear();      // return 2
myCircularDeque.isFull();       // return True
myCircularDeque.deleteLast();   // return True
myCircularDeque.insertFront(4); // return True
myCircularDeque.getFront();     // return 4

 

Constraints:

  • 1 <= k <= 1000
  • 0 <= value <= 1000
  • At most 2000 calls will be made to insertFront, insertLast, deleteFront, deleteLast, getFront, getRear, isEmpty, isFull.

💻 Lời Giải

C++ 0641-design-circular-deque.cpp 
class MyCircularDeque {
private:
    deque<int> dq;
    int k;
    
public:
    MyCircularDeque(int k) {
        this->k = k;
    }
    
    bool insertFront(int value) {
        if (dq.size() == k) {
            return false;
        }
        dq.push_front(value);
        return true;
    }
    
    bool insertLast(int value) {
        if (dq.size() == k) {
            return false;
        }
        dq.push_back(value);
        return true;
    }
    
    bool deleteFront() {
        if (dq.empty()) 
        {
            return false;
        }
        dq.pop_front();
        return true;
    }
    
    bool deleteLast() {
        if (dq.empty()) 
        {
            return false;
        }
        dq.pop_back();
        return true;
    }
    
    int getFront() {
        if (dq.empty()) 
        {
            return -1;
        }
        return dq.front();
    }
    
    int getRear() {
        if (dq.empty()) 
        {
            return -1;
        }
        return dq.back();
    }
    
    bool isEmpty() {
        return dq.empty();
    }
    
    bool isFull() {
        return dq.size() == k;
    }
};

/**
 * 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();
 */