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 10using 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;}