LinkList与ArrayList

1.LinkList

• java实现双向链表

 //链表节点模型
 private static class Node<E> {
        E item;
        Node<E> next;
        Node<E> prev;

        Node(Node<E> prev, E element, Node<E> next) {
            this.item = element;
            this.next = next;
            this.prev = prev;
        }
    }

2.ArrayList

//初始化大小为10；
int DEFAULT_CAPACITY = 10;
//存储结构为数组
private transient Object[] elementData;
//扩容方式,扩大一倍，复制数组
private void grow(int minCapacity) {
        int oldCapacity = elementData.length;
        int newCapacity = oldCapacity + (oldCapacity >> 1);
        elementData = Arrays.copyOf(elementData, newCapacity);
    }

3.HashSet

//底层为hashMap，默认为16；
 public HashSet(Collection<? extends E> c) {
        map = new HashMap<>(Math.max((int) (c.size()/.75f) + 1, 16));
        addAll(c);
    }
//hashSet对象为key，value为固定的object对象的hashMap，具体看hashMap方法
  public boolean add(E e) {
        return map.put(e, PRESENT)==null;
    }