数据结构(3)栈

public class Stack {
    private List 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);
    }
}