Reverse Nodes in k-Group

leetcode 25

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    void reverseSub(ListNode* head, ListNode** new_head,
                    ListNode** next_head, ListNode** tail, int k)
    {
        ListNode* tmp[k] = {NULL};
        ListNode* p = head;
        int i = 0,j;
        while(inext;
        }
        if (i == k)
        {
            for (j=0; jnext = NULL;
            j = k -1;
            while (j>0)
            {
                tmp[j]->next = tmp[j-1];
                j--;
            }
            tmp[0]->next = p;
            *new_head = tmp[k-1];
            *tail = tmp[0];
            *next_head = p;
        }
        else
        {
            *new_head = head;
            *next_head = NULL;
            *tail = NULL;
        }
    }
    ListNode* reverseKGroup(ListNode* head, int k) {
        ListNode *res_head =NULL;
        ListNode *new_head = NULL;
        ListNode *tail = NULL;
        ListNode *pre_tail = NULL;
        ListNode *cur_process = head;
        ListNode *next_process = NULL;
        while(cur_process)
        {
            reverseSub(cur_process, &new_head, &next_process, &tail, k);
            if (res_head == NULL)
            {
                res_head = new_head;
            }
            if (pre_tail)
                pre_tail->next = new_head;
            cur_process = next_process;
            next_process = NULL;
            pre_tail = tail;
        }
        return res_head;
    }
};