包含min函數的棧的c++實現

題目：

定義棧的資料結構，要求添加一個min函數，能夠得到棧的最小元素。
要求函數min、push以及pop的時間複雜度都是O(1)。

 

C++實現：

輸入格式是：

1 10

2

1 代表push，後面的數字是要push的內容，2代表pop

代碼如下：

#include <iostream>#include <fstream>#include <string>using namespace std;template <class T>class MinStackElement{public:    T data; // the data stored    T min; // the minimum element under the current element};template <class T>class MinStack{public:    MinStack(int max_size);    void push(T new_data);    T pop();    T minElement();private:    MinStackElement<T> *elements;    int size;    int top;};template <class T>MinStack<T>::MinStack(int max_size){    elements = new MinStackElement<T>[max_size];    size = max_size;    top = 0;}template <class T>void MinStack<T>::push(T new_data){    top ++;    elements[top - 1].data = new_data;    if(top == 1)    {        elements[top - 1].min = new_data;    }    else    {        if(new_data < elements[top - 2].min)        {            elements[top - 1].min = new_data;        }        else        {            elements[top - 1].min = elements[top - 2].min;        }    }}template <class T>T MinStack<T>::pop(){    if(top == 0)        return T();    T value;        value = elements[top - 1].data;    top --;    return value;}template <class T>T MinStack<T>::minElement(){    return elements[top - 1].min;}int main() {    ifstream fin ("minstack.in");    ofstream fout ("minstack.out");    int instruction, num;    MinStack<int> min_stack(50);        if(fin.good() == false)    {        fout << "file open failed" << endl;        return 0;    }        while(true)    {        if(fin.eof())            break;                fin >> instruction;                    if(instruction == 1)        {            fin >> num;            min_stack.push(num);            fout << "push : " << num << ", the minimum element : " << min_stack.minElement() << endl;        }        else if(instruction == 2)        {            num = min_stack.pop();            fout << "pop : " << num << ", the minimum element : " << min_stack.minElement() << endl;        }    }}

範例輸入：

1 101 41 111 51 81 90221 61 21 3022

範例輸出：

push : 10, the minimum element : 10push : 4, the minimum element : 4push : 11, the minimum element : 4push : 5, the minimum element : 4push : 8, the minimum element : 4push : 90, the minimum element : 4pop : 90, the minimum element : 4pop : 8, the minimum element : 4push : 6, the minimum element : 4push : 2, the minimum element : 2push : 30, the minimum element : 2pop : 30, the minimum element : 2pop : 2, the minimum element : 4