Rotate List

题目61：Rotate List

题目描述：

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.

题目分析：

看了别人的做法，挺好的哈。

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* rotateRight(ListNode* head, int k) {
if (head == nullptr || k == 0)
return head;
ListNode *mov;
int len, steps;
mov = head;
len = 1;
steps = 0;
while (mov->next) {
++ len;
mov = mov->next;
}
if (k % len == 0)
return head;
mov->next = head;
steps = len - (k % len);
while (steps) {
mov = mov->next;
-- steps;
}
head = mov->next;
mov->next = nullptr;
return head;
}
};

参考：

[1] http://fisherlei.blogspot.com/2013/01/leetcode-rotate-list.html