Question

1. What will be the final linked-list after executing the following method on the given input singly linked-list? Consider that the singly linked-list does not have a tail reference.

Input: 1->2->3->4->5->6->7->8->null                                                                                                 

void method(list){

if(list.head == null) return;

Node slow_ref = list.head;

Node fast_ref = list.head;

Node prevS = null;

Node prevF = null;

while(fast_ref != null && fast_ref.next != null){

prevS = slow_ref;

slow_ref = slow_ref.next;

prevF = fast_ref;

fast_ref = fast_ref.next.next;

}

prevS.next = slow_ref.next;

prevF.next.next = slow_ref;

slow_ref.next = null;

}

Answer 1

After the while loop terminates

slow_ref points to 5

fast_ref points to null

prevS points to 4

prevF points to 7

After the execution of next 3 lines after while loop

Final linked list will be

1 -> 2 -> 3 -> 4 -> 6 -> 7 -> 8 -> 5 -> null

If you have any doubt, feel free to ask in the comments.