LinkedList

LinkedList 

easy to expend, such as insert or delete

each element is a separate object : Node

disadvantage: need more memory to store reference to next node( extra 4 bytes on 32-bit CPU)

Two type: 

1 singly linked list

2 double linked list

ps : circular linked list : last node points back to first node( head)

Clone:  If we simply use the clone() method from the Object class, we will get the following structure called a "shallow" copy:

linkedlist 实现 可以参照此处代码

其中内部类实现iterator，比较有意思！

注意iterator通常需要实现三个函数

• AnyType next() - returns the next element in the container
• boolean hasNext() - checks if there is a next element
• void remove() - (optional operation).removes the element returned by next()

 /*******************************************************
 *  The Iterator class
 ********************************************************/

   public Iterator<AnyType> iterator()
   {
      return new LinkedListIterator();
   }

   private class LinkedListIterator  implements Iterator<AnyType>
   {
      private Node<AnyType> nextNode;

      public LinkedListIterator()
      {
         nextNode = head;
      }

      public boolean hasNext()
      {
         return nextNode != null;
      }

      public AnyType next()
      {
         if (!hasNext()) throw new NoSuchElementException();
         AnyType res = nextNode.data;
         nextNode = nextNode.next;
         return res;
      }

      public void remove() { throw new UnsupportedOperationException(); }
   }