not bad, mate.

Please do not just post chatGPT explanations here. It's basically just the code in plain text and should at least have the spoiler flag.

Can someone explain me this solution? Ty!

ty for this example)

My apologize, I didn't express my opinion correctly. I absolutely agree your opinion. Just so much cases let me always take care of performance issue.

I wouldn't say you "shoudln't". It depends on how frequently this method is invoked. But this solution is way more readable than any of those performance optimized implementations.
Until performance becomes an issue, I favor readable/understandable implementations over fast ones.

For performance shouldn't use any string operation.

I can't find chars() method's description in javadoc. What is it?

chars() returns an IntStream of the char values in a given CharSequence

i am wondering what dose .chars() do? sorry for silly question

it's cool but too hard fom me .....

i keep forgetting to use .chars() ty