题解 | #字符串排序#

package main

import (
	"bufio"
	"fmt"
	"os"
	"sort"
	"unicode"
)

func main() {
	in := bufio.NewScanner(os.Stdin)
	in.Scan()
	chars := []rune(in.Text())

	var letters []rune
	otherChars := make([]bool, len(chars))
	for i, c := range chars {
		if !unicode.IsLetter(c) {
			otherChars[i] = true
			continue
		}
		letters = append(letters, c)
	}

	sort.SliceStable(letters, func(i, j int) bool {
		return unicode.ToLower(letters[i]) < unicode.ToLower(letters[j])
	})

	for i, c := range chars {
		if otherChars[i] {
			fmt.Printf("%c", c)
			continue
		}
		fmt.Printf("%c", letters[0])
		letters = letters[1:]
	}
}