Leetcode -- Reverse Nodes in k-Group

Apr.05, 2014 Ugly Solution, can improve

 /**  
  * Definition for singly-linked list.  
  * struct ListNode {  
  *   int val;  
  *   ListNode *next;  
  *   ListNode(int x) : val(x), next(NULL) {}  
  * };  
  */  
 class Solution {  
 public:  
   ListNode *reverseKGroup(ListNode *head, int k) {  
     if(head == NULL) {  
       return head;  
     }  
     ListNode * dummyHead = new ListNode(-1);  
     dummyHead->next = head;  
     ListNode * follower = dummyHead;  
     ListNode * faster = dummyHead;  
     while(faster != NULL && follower != NULL) {  
       int i = 0;  
       for(; i < k && faster != NULL; ++i) {  
         faster = faster->next;  
       }  
       if(faster == NULL) {  
         break;  
       }  
       ListNode * temp = faster->next;  
       faster->next = NULL;  
       ListNode * ret = reverseLinkedList(follower->next);  
       follower->next = ret;  
       ListNode * p = follower;  
       while(p->next != NULL) {  
         p = p->next;  
       }  
       p->next = temp;  
       follower = p;  
       faster = p;  
     }  
     return dummyHead->next;  
   }  
   ListNode *reverseLinkedList(ListNode *head) {  
     ListNode * dummyHead = new ListNode(-1);  
     dummyHead->next = head;  
     ListNode * p = dummyHead;  
     ListNode * result = new ListNode(-1);  
     ListNode * q = result;  
     while(p->next != NULL) {  
       while(p->next != NULL && p->next->next != NULL) {  
         p = p->next;  
       }  
       q->next = p->next;  
       p->next = NULL;  
       p = dummyHead;  
       q = q->next;  
     }  
     delete dummyHead;  
     ListNode * ret = result->next;  
     result->next = NULL;  
     delete result;  
     return ret;  
   }  
 };