[ADS] SpecialStack

import java.util.Stack;

public class SpecialStack {

    Stack stack;
    Stack min;

    public SpecialStack() {
        this.stack = new Stack();
        this.min = new Stack();
    }

    public boolean isEmpty() {
        return stack.isEmpty();
    }

    public void push(int x) {
        if (stack.isEmpty()) {
            stack.push(x);
            min.push(x);
        } else {
            /* Just add it to the actual stack */
            stack.push(x);
            /* Get current minimum (only element in min stack)*/
            int current = (int) min.pop();
            if (current < x) {
                min.push(current);
            } else {
                min.push(x);
            }

        }
    }

    public int pop() {
        return (int) stack.pop();
    }

    public int peek() {
        return (int) stack.peek();
    }

    public int getMin() {
        return (int) min.peek();
    }

    @Override
    public String toString() {
        return "SpecialStack{" +
                "stack=" + stack +
                '}';
    }

    public static void main(String[] args) {
        SpecialStack stack = new SpecialStack();

        for (int i = 0; i < 10; i += 2) {
            stack.push(i);
        }

        System.out.println(stack.toString());

        System.out.println(stack.isEmpty());
        System.out.println(stack.peek());
        System.out.println(stack.getMin());
        stack.push(-2);
        System.out.println(stack.toString());
        System.out.println(stack.getMin());

    }
}