Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• getMin() -- Retrieve the minimum element in the stack.

class MinStack {private:    stack
     
       sta;    stack
      
        minsta;public:    void push(int x) {        sta.push(x);        if(minsta.empty()||(!minsta.empty()&&x<=minsta.top()))        minsta.push(x);    }    void pop() {        if(sta.empty())return;        if(sta.top()==minsta.top())minsta.pop();        sta.pop();    }    int top() {        if(sta.empty())return INT_MAX;        return sta.top();    }    int getMin() {        if(minsta.empty())return INT_MAX;        return minsta.top();    }};