18天算法基础系列课（四）栈

public class Stack<E> {
   private List<E> list = new ArrayList<>();
   
   public void clear() {
      list.clear();
   }
   
   public int size() {
      return list.size();
   }

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

   public void push(E element) {
      list.add(element);
   }


   public E pop() {
      return list.remove(list.size() - 1);
   }


   public E top() {
      return list.get(list.size() - 1);
   }
}
```
```