剑指offer-反转链表

public class 反转链表 {

public ListNode ReverseList(ListNode head) {
ListNode lastNode = null;
ListNode nextNode = null;
ListNode revHead = null;

while (head != null) {
nextNode = head.next;
head.next = lastNode;
if (nextNode == null)
revHead = head;
lastNode = head;
head = nextNode;
}
return revHead;
}

}