题解 | #字符个数统计#

package main

import (
    "fmt"
)

func main() {
    var s string
    fmt.Scanf("%s\n", &s)
    count := 0
    res := make(map[string]bool)
    for _, v := range s {
        if _, ok := res[string(v)]; !ok {
            count++
            res[string(v)] = true
        }
    }
    fmt.Println(count)
}