1 # Definition for singly-linked list.
2 # class ListNode(object):
3 # def __init__(self, x):
4 # self.val = x
5 # self.next = None
6
7 class Solution(object):
8 def removeNthFromEnd(self, head, n):
9 """
10 :type head: ListNode
11 :type n: int
12 :rtype: ListNode
13 """
14 if not head:
15 return None
16 dummy=ListNode(-1)
17 dummy.next=head
18
19 for i in range(n):
20 if(head):
21 head=head.next
22 else:
23 return None
24
25 if(head==None):
26 return dummy.next.next
27
28 slow=dummy.next
29 while(head.next):
30 head=head.next
31 slow=slow.next
32
33 slow.next=slow.next.next
34
35 return dummy.next
