Reorder linked list

ListNode.java

package com.interviewbytes.linkedlists;

public class ListNode {
    int val;
    ListNode next;

    ListNode(int x) {
        val = x;
    }
}

ReoderList.java

package com.interviewbytes.linkedlists;

public class ReoderList {


    public void reorderList(ListNode head) {

        if (head == null || head.next == null) return;

        ListNode slow = head;
        ListNode fast = head;

        while (fast != null && fast.next != null) {
            slow = slow.next;
            fast = fast.next.next;
        }

        ListNode reversed = null;
        while (slow != null) {
            ListNode next = slow.next;
            slow.next = reversed;
            reversed = slow;
            slow = next;
        }

        ListNode current = new ListNode(0);

        boolean odd = true;
        while (head != null && reversed != null) {
            if (odd) {
                current.next = head;
                head = head.next;
            } else {
                current.next = reversed;
                reversed = reversed.next;
            }

            current = current.next;
            odd = !odd;
        }

    }
}