第六版Cracking the Coding Interview题目2.3，题目如下：

Delete Middle Node: Implement an algorithm to delete a node in the middle (i.e., any node but the first and last node, not necessarily the exact middle) of a singly linked list, given only access to that node.
EXAMPLE
Input: the node c from the linked list a - >b- >c - >d - >e- >f
Result: nothing is returned, but the new linked list looks like a - >b- >d - >e- >f

题目的要求为得到单链表中间的一个节点，在不能访问链表头的情况下删除这个节点。那么需要做的是将下一个节点的数据拷贝到当前节点，然后删除下一个节点。

def deleteMiddleNode(node):
    if node is None or node.getNext() is None:
        raise ValueError('input node cannot be None or the last node')
    nextNode = node.getNext()
    node.setItem(nextNode.getItem())
    node.setNext(nextNode.getNext())
    del nextNode