strlen（s）每次循环都会计算一次长度
by Michael_Liu @ 2023-10-20 17:17:48
然后复杂度就由O(N)变为O(N^2)了
by Michael_Liu @ 2023-10-20 17:19:14
strlen 是 $O(|S|)$ 的
by Esawkm @ 2023-10-20 17:19:35
懂了懂了，谢谢大佬
by yiban202241040105 @ 2023-10-21 09:38:15