LeetCode 61

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.

 /*************************************************************************
     > File Name: LeetCode061.c
     > Author: Juntaran
     > Mail: JuntaranMail@gmail.com
     > Created Time: Tue 17 May 2016 18:47:57 PM CST
  ************************************************************************/

 /*************************************************************************

     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.

  ************************************************************************/

 #include <stdio.h>
 /**
  * Definition for singly-linked list.
  * struct ListNode {
  *     int val;
  *     struct ListNode *next;
  * };
  */
 struct ListNode* rotateRight(struct ListNode* head, int k)
 {
     struct ListNode* fast = head;
     struct ListNode* slow = head;
     struct ListNode* newhead = head;
     int length = ;

     if( head == NULL || k <  )
     {
         return head;
     }

     while( fast->next != NULL )
     {
         fast = fast->next;
         length ++;
     }
     fast = head;
     k = k % length;
 //  printf("%d %d\n",k,length);

     while( k >  )
     {
         fast = fast->next;
         if( fast == NULL )
         {
             return head;
         }
         k --;
     }

     while( fast->next != NULL )
     {
         slow = slow->next;
         fast = fast->next;
     }
     fast->next = head;
     newhead = slow->next;
     slow->next = NULL;

     return newhead;
 }