Hi Thanks for the comment. There is one big difference: unicode support. I did this for the unicode support, this way the input string supports unicode input. If you use string directly it is an immutable byte slice and fails for unicode. If you are this hungry for the code performance you should use C or assembly language! The Go code should be clean and reusable , I believe. Repent, repent, premature optimization is a sin :)

in Golang, for using slices in a string, you don't need to convert it n=to a rune array, the own string it's able to slice.