leetcode -- Remove Nth Node From End of List -- 简单重点

https://leetcode.com/problems/remove-nth-node-from-end-of-list/

two pointers to find the Nth Node from the end

class Solution(object):
    def removeNthFromEnd(self, head, n):
        """ :type head: ListNode :type n: int :rtype: ListNode """
        i = head
        j = head
        for k in xrange(n - 1):
            i = i.next

        dummy_node = ListNode(0)
        dummy_node.next = head
        pre_j = dummy_node
        while i.next:
            pre_j = j
            i,j = i.next, j.next

        pre_j.next = j.next

        return dummy_node.next