4 из 8 тестов

unpack.go

@@ -2,28 +2,78 @@ package unpackstring
 
 import (
 	"errors"
-	"regexp"
+	"strconv"
+	"strings"
+	"unicode"
 )
 
 var ErrInvalidString = errors.New("invalid string")
 
+type state int
+
+const (
+	start state = iota
+	escape
+	number
+)
+
 func Unpack(str string) (string, error) {
-	// Place your code here.
-	err := CheckString(str)
-	if err != nil {
-		return "", err
+	var currentState state = start
+	var result strings.Builder
+	numOfRepeat := 1
+	//if firstCheckString(&str) == true {
+	//	return "", ErrInvalidString
+	//}
+
+	var runeArray = []rune(str)
+
+	if len(runeArray) > 0 && unicode.IsDigit(runeArray[0]) {
+		return "first rune is digit", ErrInvalidString
 	}
 
+	for i, char := range runeArray {
+
+		switch currentState {
+		case start:
+			if unicode.IsDigit(char) {
+				currentState = number
+				numOfRepeat, _ = strconv.Atoi(string(char))
+			} else if char == '\\' {
+				currentState = escape
+			} else {
+				currentState = start
+				result.WriteRune(char)
+			}
+		case number:
+			if unicode.IsDigit(char) {
+				return "", ErrInvalidString
+			}
+			repStr, err := repeatRune(runeArray[i-2], numOfRepeat)
+			if err != nil {
+				res := result.String()
+				result.Reset()
+				result.WriteString(res[0 : len(res)-1])
+			}
+			result.WriteString(repStr)
+			currentState = start
+			result.WriteRune(char)
+		case escape:
+			result.WriteRune(char)
+
+		}
+
+	}
+
+	return result.String(), nil
+
+}
+
+func repeatRune(char rune, numOfRepeat int) (string, error) {
+	if numOfRepeat > 0 {
+		return strings.Repeat(string(char), numOfRepeat-1), nil
+	}
+	if numOfRepeat == 0 {
+		return "", errors.New("zero repeat")
+	}
 	return "", nil
 }
-
-func CheckString(str string) error {
-
-	re, _ := regexp.Compile(`^\d|\d{2,}`)
-
-	if re.MatchString(str) == true {
-		return ErrInvalidString
-	}
-
-	return nil
-}