All combinations of uniq symbols

main.go

package module

import (
	"fmt"
	"strings"
)
func main() {

	str := "fgfwfhh"
  
	//replace repeated runes to blanks
	rs := []rune(str)
	for i := 0; i < len(rs); i++ {
		for j := i + 1; j < len(rs); j++ {
			if rs[j] == rs[i] {
				rs[j] = ' '
			}
		}
	}
	// remove blanks
	str = strings.ReplaceAll(string(rs), " ", "")
	recursiveStr("", str)
}

func recursiveStr(variants string, s string) {

	for _, r := range s {
		recursiveStr(variants+string(r), strings.ReplaceAll(s, string(r), ""))
	}

	if len(s) == 0 {
		fmt.Println(variants)
	}
}