Look at the implementation of the strings.ToUpper / strings.ToLower function – there is a loop inside. So that you are using more than 1 loop in your solution.

https://cs.opensource.google/go/go/+/go1.20.4:src/strings/strings.go;l=585
https://cs.opensource.google/go/go/+/go1.20.4:src/strings/strings.go;l=625

What if the string contains runes that are neither uppercase or lowercase (not a letter, but a number or symbol)? unicode considers them neither upper or lowercase. len(str) also returns the number of bytes in the string, not the number of runes.

weird, for me it works in 1100ms, 10 times faster than the limit.

Great solution! I believe we can actually include second 'if' inside the loop and
have a chance to reduce time complexity by up to 50%

oh ! didn't know there was a unicode.IsUpper function

awesome solution

I had a timeout error with this kind os solution...

because it's not a list. Look at the documentation of the fonction generating it.

It's so fast!!

I'd like to know as well

Can you explain how this works?

can i ask why is it bad ?
what implicit coerction means ?