【LeetCode】队列&栈

队列&栈

队列：先入先出的数据结构

1、设计循环队列

class MyCircularQueue {
private:
    vector<int> data;
    int head;
    int tail;
    int size;
public:
    /** Initialize your data structure here. Set the size of the queue to be k. */
    MyCircularQueue(int k) {
        data.resize(k);
        head=-1;
        tail=-1;
        size=k;
    }
    
    /** Insert an element into the circular queue. Return true if the operation is successful. */
    bool enQueue(int value) {
        if(isFull())
            return false;
        if(isEmpty())
        {
            head=0;
        }
        tail=(tail+1)%size;
        data[tail]=value;
        return true;
    }
    
    /** Delete an element from the circular queue. Return true if the operation is successful. */
    bool deQueue() {
        if(isEmpty())
        {
            return false;
        }
        if(head==tail)
        {
            head=-1;
            tail=-1;
            return true;
        }
        head=(head+1)%size;
        return true;
    }
    
    /** Get the front item from the queue. */
    int Front() {
        if(isEmpty())
            return -1;
        return data[head];
    }
    
    /** Get the last item from the queue. */
    int Rear() {
        if(isEmpty())
            return -1;
        return data[tail];
    }
    
    /** Checks whether the circular queue is empty or not. */
    bool isEmpty() {
        return head==-1;
    }
    
    /** Checks whether the circular queue is full or not. */
    bool isFull() {
        return (tail+1)%size==head;
    }
};

/**
 * 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();
 */