链表_leetcode19

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

class Solution(object):
    def removeNthFromEnd(self, head, n):
        """
        :type head: ListNode
        :type n: int
        :rtype: ListNode
        """

        dummyHead = ListNode(0)
        dummyHead.next = head

        p = dummyHead
        q = p

        for i in range(n+1):
            q = q.next


        while q:
            p = p.next
            q = q.next

        delNode = p.next
        p.next = delNode.next

        return dummyHead.next