题目来源
https://leetcode.com/problems/rotate-list/
Given a list, rotate the list to the right by k places, where k is non-negative.
For example:
Given 1->2->3->4->5->NULL and k = 2,
return 4->5->1->2->3->NULL.
题意分析
Input:a list of node
Output:a list of node shift to right
Conditions:链表右移
题目思路
总体思路是链表右移，关键是右移k可能大于实际长度，所以先遍历一次求长度，然后再求模得到真正右移数量
PS：对于链表操作，每次在前面添加一个节点这个方法很好用，特别注重边界条件
PS2：尽量用xrange代替range
AC代码（Python）
__author__ = 'YE' # Definition for singly-linked list.
class ListNode(object):
def __init__(self, x):
self.val = x
self.next = None class Solution(object):
def rotateRight(self, head, k):
"""
:type head: ListNode
:type k: int
:rtype: ListNode
"""
if k == 0 or head == None:
return head addFirst = ListNode(0)
addFirst.next = head
# move variable
p = addFirst
#the length of list
count = 0
while p.next != None:
p = p.next
count += 1
p.next = addFirst.next
#the real step to shift right
step = count - (k % count)
p = addFirst.next
for i in xrange(1, step):
p = p.next
head = p.next
p.next = None return head