题目:1-1-2-3-3-3-4-5-6-6-7,删除重复节点后返回2-4-5-7
def delete_duplicate(head): h = Node(0) k = h p = head if not p or not p.next: return head q = p.next if p.val!=q.val: k.next = p k = k.next while q.next: if q.val!=p.val and q.val!=q.next.val: k.next = q k = k.next p = q q = q.next if p.val!=q.val: k.next = q k = k.next k.next = None return h.next
注:不重复节点判断标准为,和前、后节点都不相同,注意头节点和尾结点要单独判断。