题解 | #反转链表#
反转链表
https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca
/*class ListNode {
* val: number
* next: ListNode | null
* constructor(val?: number, next?: ListNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.next = (next===undefined ? null : next)
* }
* }
*/
/**
* 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
*
* @param head ListNode类
* @return ListNode类
*/
export function ReverseList(head: ListNode): ListNode {
// write code here
if (!head?.next) return head
let currentNode = head.next
let previousNode = head
head.next = null
while(currentNode) {
// store temporarily
const nextNode = currentNode.next
// reverse
currentNode.next = previousNode
// refresh
previousNode = currentNode
currentNode = nextNode
// check if end
if (!currentNode) return previousNode
}
}
