链表 - 以 K 为一组反转链表

Question

I was following this Java solution to understand the given problem

I got most of it, the reversal logic, the recursion part but under the main method, I don't get why we are assigning the head value to the value returned by the reverse method.

llist.head = llist.reverse(llist.head, 3); 

Answer 1

In llist.reverse(llist.head, 3); it will reverse the head list with specified length(3) and assigning back to llist.head.

1->2->3->4->5->6->7->8->NULL, K = 3

After first iteration

3->2->1 ->4->5->6->7->8->NULL - it reverse the first 3 elements and in second iteration

3->2->1-> 6->5->4 ->7->8->NULL and in last iteration 3->2->1->6->5->4->8->7->NULL

finally llist.head holds the 3->2->1->6->5->4->8->7->NULL