Question

leetcode, 用python为什么提交时报错：AttributeError: 'NoneType' object has no attribute 'next' 啊

# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None

class Solution(object):
def removeElements(self, head, val):
"""
:type head: ListNode
:type val: int
:rtype: ListNode
"""
cur = ListNode(0)
cur.next = head
p = cur
while p.next:
if p.next.val == val:
cur.next = cur.next.next
else:
p = p.next
return cur.next

Answer 1

估计是solution的问题，改动一下代码就可以了：

class Solution(object):
    def removeElements(self, head, val):
        """
        :type head: ListNode
        :type val: int
        :rtype: ListNode
        """
        cur = ListNode(0)
        cur.next = head
        p = cur
        cur.next=None
        while p.next:            
            if p.next.val == val: 
                cur.next=p.next               
                p.next = p.next.next
                break
            p = p.next                            
        return cur.next

Answer 2

因为你的ListNode到达尾部了，尾部的next为None，再循环时，寻找None的next，就出错