Golang：在不重复的字符串中查找第一个字符

Question

I'm trying to write a function that returns the finds first character in a String that doesn't repeat, so far I have this:

package main

import (
    "fmt"
    "strings"
)

func check(s string) string {

    ss := strings.Split(s, "")
    smap := map[string]int{}

    for i := 0; i < len(ss); i++ {
        (smap[ss[i]])++

    }

    for k, v := range smap {

        if v == 1 {
            return k
        }
    }

    return ""
}

func main() {
    fmt.Println(check("nebuchadnezzer"))

}

Unfortunately in Go when you iterate a map there's no guarantee of the order so every time I run the code I get a different value, any pointers?

Answer 1

Using a map and 2 loops : play

func check(s string) string {
    m := make(map[rune]uint, len(s)) //preallocate the map size
    for _, r := range s {
        m[r]++
    }

    for _, r := range s {
        if m[r] == 1 {
            return string(r)
        }
    }
    return ""
}

The benfit of this is using just 2 loops vs multiple loops if you're using strings.ContainsRune, strings.IndexRune (each function will have inner loops in them).