[nonameiguess]

You can even demonstrate a similar concept with English and Latin characters. There is no single thing called a "grapheme" linguistically. There are actually two different types of graphemes. The character sequence "sh" in English is a single referential grapheme but two analogical graphemes. Depending on what the specification means, "short" could be reversed as either "trosh" or "trohs". That's without getting into transliteration. The word for Cherokee in the Cherokee language is "Tsalagi" but the "ts" is a Latin transliteration of a single Cherokee character. Should we count that as one grapheme or two?

Of course, if an interviewer is really asking you how to do this, they're probably either 1) working in bioinformatics, in which case there are exactly four ASCII characters they really care about and the problem is well-defined, or 2) it's implementing something like rev | cut -d '-' -f1 | rev to get rid of the last field and it doesn't matter how you implement "rev" just so long as it works exactly the same in reverse and you can always recover the original string.

[Spivak]

The fact that how to reverse a piece of text is locale dependent doesn't mean it's impossible. Basically and transformation on text will be locale dependent. Hell, length is locale dependent.