迭代
代码语言：javascript复制class Solution {
public ListNode reverseList(ListNode head) {
if (head == null) return head;
ListNode a=head, b=head.next;
head.next = null;
while (b != null) {
ListNode c = b.next;
b.next = a;
a = b;
b = c;
}
return a;
}
}递归
代码语言：javascript复制class Solution {
public ListNode reverseList(ListNode head) {
if (head==null || head.next==null) {
return head;
}
ListNode res = reverseList(head.next);
head.next.next = head;
head.next = null;
return res;
}
}
