Memory is not a constraint. In a single iteration(NOTE: you
can't go back), how will you find out the 10th last
node/item in a linked list.

Answer Posted / ranjani

The approach is to have 2 ptrs ,ptr1 and ptr2.Where ptr1
would start at the first node of the linked list and ptr2
would be at the kth position from ptr1.In this case k=10.

From there on until ptr2->next!=null keep moving ptr1 and
ptr2 by one each.When ptr2 reached the last element of the
linked list.Ptr1 would be pointing to the 10th (kth) last
element.

Example:

1->2->3->4->5->6->7->8->9->10->11->12. In this case 10th
last element would be 3.

Start with ptr1 at node 1 and ptr2 at node 10.
Now till ptr2->next!=null ptr1=ptr1->next and ptr2=ptr2->next.

This way when ptr2 reaches 12 ptr1 would be at 3,which is
the 10th last element.

Is This Answer Correct ?    8 Yes 0 No



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