LeetCode: Remove Nth Node From End of List

/**
 * Created by hzhou on 5/6/15. [email protected]
 */
public class RemoveNthNodeFromEndOfList {
    public ListNode removeNthFromEnd(ListNode head, int n) {
        if (head == null) {
            return null;
        }
        if(n == 0) return head;
        ListNode preHead = new ListNode(0);
        preHead.next = head;
        ListNode c1 = head;
        ListNode c2 = head;
        while (n > 0) {
            c2 = c2.next;
            n--;
        }
        if(c2 == null) {
            return head.next;
        }
        while(c2.next != null) {
            c1 = c1.next;
            c2 = c2.next;
        }
        c1.next = c1.next.next;
        return head;
    }
}