фикс Golang

main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"math/cmplx"
 	"strconv"
+	"strings"
 )
 
 func main() {
@@ -32,7 +33,7 @@ func fractal(size int, depth int, g2 complex128, g3 complex128) string {
 	var yi float64 = -2
 	var xi float64 = -2
 
-	var code string
+	var code strings.Builder
 
 	for y := 0; y < size; y++ {
 		zy = float64(y)*(yf-yi)/float64(size-1) + yi
@@ -41,12 +42,12 @@ func fractal(size int, depth int, g2 complex128, g3 complex128) string {
 			z = complex(zx, zy)
 			for i := 0; i < depth; i++ {
 				if cmplx.Abs(z) > 2 {
-					code += strconv.FormatInt(int64(i), 10)
+					code.WriteString(strconv.FormatInt(int64(i), 10))
 					break
 				}
 				z = (cmplx.Pow(z, 4) + g2*cmplx.Pow(z, 2)/2 + 2*g3*z + cmplx.Pow(g2, 2)/16) / (4*cmplx.Pow(z, 3) - g2*z - g3)
 			}
 		}
 	}
-	return code
+	return code.String()
 }