【编程题目】设计包含 min 函数的栈

/*
2.设计包含 min 函数的栈（栈）
定义栈的数据结构，要求添加一个 min 函数，能够得到栈的最小元素。
要求函数 min、push 以及 pop 的时间复杂度都是 O(1)。
*/
#include <stdio.h>
#include <stdlib.h>

typedef int Elemtype;

typedef struct Stack_Elem
{
    Elemtype data;
    Stack_Elem * p_next;
};
typedef struct My_Stack
{
    Elemtype min;
    Stack_Elem * top;
}My_Stack;

Elemtype Stack_Min(My_Stack S)
{
    return S.min;
}

void Stack_Push(My_Stack* S, Elemtype e)
{
    Stack_Elem * new_element = (Stack_Elem *)malloc(sizeof(Stack_Elem));
    new_element->data = e;
    new_element->p_next = S->top;
    S->top = new_element;

    S->min = (S->min < e) ? S->min : e;
}

Elemtype Stack_Pop(My_Stack* S)
{
    if(S == NULL)
    {
        printf("error");
        return -1;
    }
    Stack_Elem * pop_elem = S->top;
    S->top = pop_elem->p_next;
    pop_elem->p_next = NULL;
    Elemtype e = pop_elem->data;
    if(e == S->min)
    {
        Elemtype min = S->top->data;
        Stack_Elem * p = S->top;
        while(p->p_next != NULL)
        {
            if (p->data < min)
            {
                min = p->data;
            }
            p = p->p_next;
        }
        S->min = min;
    }

    free(pop_elem);
    return e;
}

int main()
{
    My_Stack S;
    S.min = 999999;
    S.top = NULL;

    Stack_Push(&S, 5);
    Stack_Push(&S, 4);
    Stack_Push(&S, 3);
    Stack_Push(&S, 2);
    Stack_Push(&S, 1);

    Elemtype e = Stack_Min(S);

    e = Stack_Pop(&S);
    e = Stack_Pop(&S);

    e = Stack_Min(S);

    return 0;
}

// minStatck.cpp : 定义控制台应用程序的入口点。
#include "stdafx.h"
#include <iostream>
#include <vector>
#include <cassert>

using namespace std;

template<typename T>
class StackSuppliedMin{
public:
    vector<T> datas;
    vector<size_t> minStack;

    void push(T data){
        datas.push_back(data);
        if (minStack.empty() || data < datas[minStack.back()])
            minStack.push_back(datas.size()-1);
    }

    void pop(){
        assert(!datas.empty());
        if (datas.back() == datas[minStack.back()])
            minStack.pop_back();
        datas.pop_back();
    }

    T min(){
        assert(!datas.empty() && !minStack.empty());
        return datas[minStack.back()];
    }

    void display(){
        cout << "datas = ";
        for (unsigned i = 0; i < datas.size(); i ++)
            cout << datas[i] << " ";
        cout << endl;
        cout << "minStack = ";
        for (unsigned i = 0; i < minStack.size(); i ++)
            cout << datas[minStack[i]] << " ";
        cout << endl;
        cout << "min = " << datas[minStack.back()] << endl << endl;
    }
};
void main()
{
    StackSuppliedMin<int> s;
    s.push(3);
    s.display();
    s.push(4);
    s.display();
    s.push(2);
    s.display();
    s.push(0);
    s.display();
    s.pop();
    s.display();
    s.pop();
    s.display();
    s.push(0);
    s.display();


}