[bushin]

> strings are simply arrays of chars

or code units/code points/grapheme clusters/emojis. Thanks to hard work of many developers string handling becomes easier over time, but I don't think it's trivial if you don't exactly specify what you mean by "string" and "character".

[nilkn]

I can't speak for chadash, but I'm pretty sure most folks who know to ask questions like this are probably going to pass the interview. They'll ask the right questions, and the problem will be simplified to a form that is solvable in a few minutes. So I don't think this is any major hurdle.

[chadash]

I think you and I are arguing semantics then. The very question "what do you mean by a string?" already indicates that you might be familiar with some of the differences between unicode and ascii, for example. In that case, I'll clarify what I mean depending on the language the candidate is most comfortable with. For example, if they plan to use C++, I might clarify that they can assume that the string is an array of chars containing letters a-z. I really just intend it as a filtering question, but someone can definitely get bonus points if they ask intelligent questions to clarify the problem.

[pastage]

You can't give those answers on computer aided code testing sites. That's why those tests needs to be long, verbose and boring so the questions will be obvious.

The human touch.