Give a \(\Theta(n)\)-time nonrecursive procedure that reverses a singly linked list of \(n\) elements. The procedure should use no more than constant storage beyond that needed for the list itself.

REVERSE-SINGLY-LINKED-LIST(x)

1 a = x.head

2 b = x.head.next

3 while b != NIL:

4      c = b.next

5      b.next = a

6      a = b

7      b = c

8 x.head = a