// 递归处理, 利用函数作用域操作当前节点和当前节点的下一个节点
const reverseList = head => {
if (head == null || head.next == null) return head
const end = reverseList(head.next)
head.next.next = head
head.next = null
return end // 返回最后一个节点,也就是反转后的头节点
};
const reverseList = head => {
let prev = null
let cur = head
while (cur) {
const next = cur.next
cur.next = prev
prev = cur
cur = next
}
return prev
}