[LeetCode] 61. Rotate List 解题思路

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.

问题：给定列表 和一个整数 k ，旋转列表最后 k 个元素至列表最前面。

关键是找到最后元素 lastOne 和 旋转后列表新的最后元素 newLastOne

     ListNode* rotateRight(ListNode* head, int k) {

         if (head == NULL) {
             return NULL;
         }

         int n = ;
         ListNode* lastOne = head;
         while (lastOne->next != NULL) {
             n++;
             lastOne = lastOne->next;
         }

         if (n == k) {
             return head;
         }

     　　int firstNum = n - (k % n);

         ListNode* newLastOne;
         newLastOne = head;
         for (int i = ; i < firstNum; i++) {
             newLastOne = newLastOne->next;
         }

         lastOne->next = head;
         head = newLastOne->next;
         newLastOne->next = NULL;

         return head;
     }