HTMLify

func reversePrefix(word string, ch byte) string {
    var stack []rune
    for _i, c := range word {
        stack = append(stack, c)
        if byte(c) == ch {
            var r string
            for i:=len(stack)-1; i>=0; i-- {
                r += string(stack[i])
            }
            return r + word[_i+1:]
        } 
    }
    return word
}