// Package encode implements run-length-encoding and decoding functions.
package encode
import (
	"log"
	"strconv"
	"strings"
	"unicode"
)
func RunLengthEncode(input string) string {
	if input == "" {
		return ""
	}
	var ret strings.Builder
	prev := rune(input[0])
	count := 0
	for i, ch := range input {
		if prev == ch {
			count++
			if i != len(input)-1 {
				continue
			}
		}
		if count > 1 {
			ret.WriteString(strconv.Itoa(count))
			count = 1
		}
		ret.WriteRune(prev)
		if i == len(input)-1 && prev != ch {
			ret.WriteRune(ch)
		}
		prev = ch
	}
	return ret.String()
}
func RunLengthDecode(input string) string {
	var counter strings.Builder
	var ret strings.Builder
	for i, ch := range input {
		if unicode.IsDigit(ch) {
			counter.WriteRune(ch)
			continue
		}
		if counter.String() != "" {
			c, err := strconv.Atoi(counter.String())
			if err != nil {
				log.Printf("error converting %q: %s", counter.String(), err)
			}
			ret.Write([]byte(strings.Repeat(string(input[i]), c)))
			counter.Reset()
			continue
		}
		ret.WriteRune(ch)
	}
	return ret.String()
}