删除链表中重复的元素

双指针

# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

#
# 
# @param head ListNode类 
# @return ListNode类
#
class Solution:
    def deleteDuplicates(self , head):
        curp = head
        # 不使用 curp.next, 避免越界判断
        nextp = head
        while curp and nextp:
            if curp.val == nextp.val:
                # 删除
                curp.next = nextp.next
            else:
                # 继续向后遍历
                curp = curp.next
            nextp = nextp.next
        return head