#### стек с максимумом
#include <iostream>
#include <sstream>
#include <string>
class Stack
{
private:
    struct X {
        int value;
        int localMax;
    };

    X *data_;
    int size;
    int top = -1;
public:
    Stack(int n): data_(new X[n]), size(n),  top(-1) { }
    void push(int value)
    {
        ++top;
        if (top == -1)
        {
            data_[top].value = value;
            data_[top].localMax = value;
        }
        else
        {
            data_[top].value = value;
            data_[top].localMax = data_[top-1].localMax < value ? value : data_[top-1].localMax;
        }

    }
    void pop() {  --top; }

    int max() const {return data_[top].localMax;  }
};
void test1(std::istream &cin, std::ostream & cout)
{
    int n;
    cin >> n;
    Stack stack(n);
    std::string command;
    int value;
    while (n--) {
        cin>> command;
        if (command == "push")
        {
            cin >>  value;
            stack.push(value);
        }
        else if (command == "pop") { stack.pop();}
        else if (command == "max") { cout << stack.max() << "\n"; }
    }
}
int main(int argc, char *argv[])
{
    {
        std::istringstream istr(std::string("5 push 1 push 2 max pop max"));
        std::string answer;
        std::ostringstream ostr(answer);
        test1(istr, ostr);
        std::cout << "ответ:\n" << ostr.str() << "\n";
        std::cout << "верный ответ 2 1 \n";
    }

    {
        std::istringstream istr("10 push 2 push 3 push 9 push 7 push 2 max max max pop max");
        test1(istr, std::cout);
        std::cout << "верный ответ 9 9 9 9 \n";
    }
        {
        std::istringstream istr("5 push 2 push 1 max pop max");
        test1(istr, std::cout);
        std::cout << "верный ответ 2 2 \n";
    }



}