[Leetcode]Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.

For example,

Given 

1->1->2

, return 

1->2

.

Given 

1->1->2->3->3

, return 

1->2->3

.

基础链表题~ 把重复得节点去掉~  维护了两个指针：pre 和 cur指针  pre指向当前不重复得第一个节点，cur往后依次扫描，如果值与pre得值相等，继续往下扫描，如果不等，把pre指针的next指向当前的cur指针，即删除与pre节点重复的节点~

class Solution:
# @param head, a ListNode
# @return a ListNode
def deleteDuplicates(self, head):
if head is None: return None
pre, cur = head, head.next
while pre != None:
while cur != None and cur.val == pre.val:
cur = cur.next
pre.next = cur
pre = pre.next
return head