双端堆栈

声明：图片及内容基于https://www.bilibili.com/video/av92597456

原理

双栈共享从分别从两端插如数据，向两端删除数据，两站共享实现节省空间

着重理解其编程理念

 

---

 

 

具体实现

#include<iostream>
using namespace std;
const int STACK_SIZE = 100;
template<class T>
class BothStack {
private:
    T* data;
    int top1, top2;                       //两个栈的头
    int size;
public:
    BothStack();                         
    BothStack(int s);                    //有参构造
    ~BothStack();                        //析构
    void push(int num, T x);             //插入：num=1代表栈1，num=2代表栈2
    T pop(int num);                      //弹栈
    T getTop(int num);                   //弹出栈头元素
    bool isEmpty(int num);               //判断是否为空
    bool isFull();                       //判断是否满
    class Empty1{};                      //类内声明异常类
    class Empty2{};
    class Full{};
};

template <class T>
BothStack<T>::BothStack() {
    size = STACK_SIZE;
    data = new T[size];
    top1 = -1;
    top2 = size;
}

template <class T>
BothStack<T>::BothStack(int s) {
    size = s;
    data = new T[size];
    top1 = -1;
    top2 = size;    
}

template <class T>
BothStack<T>::~BothStack() {
    delete[] data;
}

template <class T>
void BothStack<T>::push(int num, T x){
    if (isFull()) throw BothStack<T>::Full();   //注意抛出匿名对象
    switch (num) {
    case 1:
        data[++top1] = x;               //注意
        break;
    case 2:
        data[--top2] = x;               //注意
    default:
        break;
    }
}

template<class T>
T BothStack<T>::pop(int num) {
    switch (num) {
    case 1:
        if (isEmpty(num)) throw BothStack<T>::Empty1();
        else {
            return data[top1--];        //注意
            break;
        }
    case 2:
        if (isEmpty(num)) throw BothStack<T>::Empty2();
        else {
            return data[top2++];        //注意
            break;
        }
    default:
        break;
    }
}

template<class T>
T BothStack<T>::getTop(int num) {
    if (isEmpty(num)) {
        switch (num) {
        case 1:
            throw BothStack<T>::Empty1();
        case 2:
            throw BothStack<T>::Empty2();
        }
    }
    else {
        switch (num) {
        case 1:
            return data[top1];
        case 2:
            return data[top2];
        default:
            break;
        }
    }
 }

template<class T>
bool BothStack<T>::isEmpty(int num) {
    switch (num)
    {
    case 1:
        if (top1 == -1) return true;
        else return false;
    case 2:
        if (top2 == size) return true;
        else return false;
    default:
        break;
    }
}

template<class T>
bool BothStack<T>::isFull() {
    if (top1 + 1 == top2) return true;
    else return false;
}


int main() {
    BothStack<int> stack(2);
    try {
        //stack.pop(1); 
        //stack.pop(2);
        stack.push(2, 1);
        stack.push(2, 2);
        cout << stack.pop(2)<<endl;
        cout << stack.pop(2)<<endl;
    }
    catch (BothStack<int>::Full) {
        cout << "full"<<endl;
    }
    catch (BothStack<int>::Empty1) {
        cout << "empty1"<<endl;
    }
    catch (BothStack<int>::Empty2) {
        cout << "empty2"<<endl;
    }
    return 0;
}