main.go

package main

/*
$ cat in
8 3 7 1 2 5 6 0 9 4
decode
0728
> 7240

$ cat in
8 1 4 7 2 3 9 5 6 0
encode
257
> 435
*/

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func scan(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func atoi(v string) int {
	i, _ := strconv.Atoi(v)
	return i
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	codes := []int{}
	for i := 0; i < 10; i++ {
		codes = append(codes, atoi(scan(sc)))
	}
	s := scan(sc)
	val := scan(sc)
	out := []string{}
	if s == "encode" {
		for _, v := range val {
			intv := atoi(string(v))
			out = append(out, fmt.Sprintf("%d", codes[intv]))
		}
	} else { //decode
		for _, v := range val {
			intv := atoi(string(v))
			for i, c := range codes {
				if c == intv {
					out = append(out, fmt.Sprintf("%d", i))
				}
			}
		}
	}
	fmt.Println(strings.Join(out, ""))
}