import java.util.Stack;
public class MinStack <E extends Integer>{
private Stack<E> minStack=
new Stack<E>();
private Stack<E> element=
new Stack<E>();
public E
min(){
if (!minStack.isEmpty())
return minStack.peek();
return null;
}
public void push(E e){
element.push(e);
if (!minStack.isEmpty()){
E min=minStack.peek();
if (e.compareTo(min)<
0){
minStack.push(e);
}
else{
minStack.push(min);
}
}
else{
minStack.push(e);
}
}
public E
pop(){
if (!element.isEmpty()){
minStack.pop();
return element.pop();
}
return null;
}
public void print(){
while (!element.isEmpty()){
System.
out.print(element.pop()+
" ");
}
}
public static void main(String[] args) {
MinStack<Integer> s=
new MinStack<Integer>();
s.push(
3);
System.
out.println(s.min());
s.push(
4);
System.
out.println(s.min());
s.push(
2);
System.
out.println(s.min());
s.push(
3);
System.
out.println(s.min());
s.pop();
System.
out.println(s.min());
s.pop();
System.
out.println(s.min());
s.pop();
s.push(
0);
System.
out.println(s.min());
System.
out.println(s.minStack.size());
}
}
