Min Stack

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.

 https://leetcode.com/problems/min-stack/

import java.util.ArrayList;
import java.util.List;

class MinStack
{
    static class Element
    {
        final int value;
        final int min;
        Element(final int value, final int min)
        {
            this.value = value;
            this.min = min;
        }
    }
    private List<Element> list=new ArrayList();
    public void push(int x) 
    {
        if(list.isEmpty())
            list.add(new Element(x,x));
        else
            list.add(new Element(x,Math.min(x,list.get(list.size()-1).min)));
    }

    public void pop() 
    {
        list.remove(list.size()-1);//
    }

    public int top() 
    {
        return list.get(list.size()-1).value;
    }

    public int getMin() 
    {
        return list.get(list.size()-1).min;
    }
}

public class test
{
    public static void main(String[] args)
    {
        MinStack st=new MinStack();
        st.push(5);
        st.push(6);
//        st.pop();
        int t=st.top();
        st.push(1);
        st.push(2);
        st.push(3);
        st.push(4);
        int m=st.getMin();
    }
}