Reverse Nodes in k-Group

/**
 * 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 *dummy=new ListNode(0);
       ListNode *begin=new ListNode(0);
       ListNode *begin_prev=new ListNode(0);
       ListNode *end=new ListNode(0);
       ListNode *end_next=new ListNode(0);
       ListNode *temp=new ListNode(0);
       
       
       dummy->next=head;
       begin_prev=dummy;
       
       begin=head;
       end=head;
 
       int indicator=0;
       int i=0;
       //int initial=0;
       
    while (indicator==0) {
        i=0;
       while ((i<k-1)&&(end!=NULL)) {
           end=end->next;
           i++;
       }
       
       
       if ((i==k-2)&&(end!=NULL)) {
           indicator=0;
           end_next=end->next;
         //  if (initial=0) dummy->next=end;
       }
       else indicator=1;
       
       
       ListNode *prev=new ListNode(0);
       ListNode *current=new ListNode(0);
       ListNode *temp=new ListNode(0);
       
       prev=begin;
       current=begin->next;
       if (indicator==0) {
       i=0;
       while (i<k-1) {
           
               temp=current->next;
               current->next=prev;
               
               prev=current;
               current=temp;
               i++;
       }
       
       begin=end_next;
       end=begin;
       begin_prev->next=end;
       begin_prev=prev;
       
       }
       else {
           begin_prev->next=begin;
       }
       
    }
       
       return dummy->next;
        
    }
};