2023-9-8

9-8

链表

206. 反转链表

第一感觉直接上递归

/**
 * Definition for singly-linked list.
 * 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)
 *     }
 * }
 */

function reverseList(head: ListNode | null): ListNode | null {
    if(head===null||head.next===null){
       return head
    }
    let cur = reverseList(head.next)
    head.next.next = head
    head.next = null
    return cur    
};