Linked List 2:kReverse

public class Solution {
    public static LinkedListNode<Integer> kReverse(LinkedListNode<Integer> head, int k) {
        if(head==null)
            return head;
        if(head.next==null)
            return head;
        if(k==0)
            return head;
        LinkedListNode<Integer> h1=head,h2,t1=head;
        int count=1;
     while(count<k && t1.next!=null)
     {
         t1=t1.next;
         count++;
     }
          
            h2=t1.next;
            t1.next=null;
        

        DoubleNode ans=reversePart(h1);
        LinkedListNode<Integer> secondHead=kReverse(h2,k);
        ans.tail.next=secondHead;
        return ans.head;

    }
    private static DoubleNode reversePart(LinkedListNode<Integer> head)
    {
        if(head==null || head.next==null)
        { DoubleNode ans=new DoubleNode();
        ans.head=head;
        ans.tail=head;
        return ans;}
     
        DoubleNode ans=reversePart(head.next);
        ans.tail.next=head;
        head.next=null;
        ans.tail=ans.tail.next;
        return ans;
    }

}
class DoubleNode{
    LinkedListNode<Integer> head;
    LinkedListNode<Integer> tail;}