155. Min Stack

class MinStack {
public:
    void push(int x) {
        datas.push(x);
        if(!min_elems.empty() && min_elems.top() < x){
            min_elems.push(min_elems.top());
        }else{
            min_elems.push(x);
        }
    }

    void pop() {
        datas.pop();
        min_elems.pop();
    }

    int top() {
        return datas.top();
    }

    int getMin() {
        return min_elems.top();
    }
private:
    stack<int> datas;
    stack<int> min_elems;
};