Data Structure Linked list Interview Question:

Explain reverse a linked list iterative solution in Java?

Submitted by: Muhammad

public reverseListIteratively (Node head)
{
if (head == NULL || head.next == NULL)
return; //empty or just one node in list

Node Second = head.next;

//store third node before we change
Node Third = Second.next;

//Second's next pointer
Second.next = head; //second now points to head
head.next = NULL; //change head pointer to NULL

//only two nodes, which we already reversed
if (Third == NULL)
return;

Node CurrentNode = Third;

Node PreviousNode = Second;

while (CurrentNode != NULL)
{
Node NextNode = CurrentNode.next;

CurrentNode.next = PreviousNode;

/* repeat the process, but have to reset
the PreviousNode and CurrentNode
*/

PreviousNode = CurrentNode;
CurrentNode = NextNode;
}

head = PreviousNode; //reset the head node
}
Submitted by: Muhammad