写一个链表反转的java代码

以下是反转单向链表的Java代码：

class ListNode {
    int val;
    ListNode next;

    ListNode(int val) {
        this.val = val;
    }
}

public class Solution {
    public ListNode reverseList(ListNode head) {
        ListNode prev = null;
        ListNode curr = head;
        while (curr != null) {
            ListNode next = curr.next;
            curr.next = prev;
            prev = curr;
            curr = next;
        }
        return prev;
    }
}

以下是反转双向链表的Java代码：

class ListNode {
    int val;
    ListNode prev;
    ListNode next;

    ListNode(int val) {
        this.val = val;
    }
}

public class Solution {
    public ListNode reverseList(ListNode head) {
        ListNode curr = head;
        while (curr != null) {
            ListNode temp = curr.next;
            curr.next = curr.prev;
            curr.prev = temp;
            if (temp == null) {
                return curr;
            }
            curr = temp;
        }
        return null;
    }
}