[LC] 19. Remove Nth Node From End of List

Given a linked list, remove the n-th node from the end of list and return its head.

Example:

Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.

Note:

Given n will always be valid.

Follow up:

Could you do this in one pass?

 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         dummy = ListNode(-1)
15         dummy.next = head
16         cur, slow = dummy, dummy
17         while n > 0:
18             cur = cur.next
19             n -= 1
20         while cur.next is not None:
21             slow = slow.next
22             cur = cur.next
23         slow.next = slow.next.next
24         return dummy.next
25