O(1)时间求一个栈的最小值

/*
O(1)求出一个栈的最小值
*/
#include <iostream>
#include <stack>
#include <stdlib.h>
#define maxsize 10
using namespace std;
int main()
{
	stack<int> source;
	stack<int> compare;
	for(int i = 0;i < maxsize;i++)
	{
		int input;
		cin >> input;
		source.push(input);
	}
	int min = source.top();
	while(!source.empty())
	{
		if(min > source.top())
		{
			min = source.top();
			compare.push(min);
		}
		source.pop();
	}
	cout <<"The minimum number of the stack is: "<<min<<endl;
	return 0;
}