Move reusable functions to dedicated libraries

In order to reduce solution time in future.

Signed-off-by: Alexander Kurbatov <sir.alkurbatov@yandex.ru>

Author: alkurbatov

.golangci.yaml

@@ -88,7 +88,7 @@ linters:
     - bodyclose
     - cyclop
 #    - deadcode
-    - depguard
+#    - depguard
     - dogsled
 #    - dupl
     - durationcheck

2023/1/main.go

@@ -7,6 +7,8 @@ import (
 	"log"
 	"os"
 	"regexp"
+
+	"github.com/alkurbatov/adventofcode/internal/strmod"
 )
 
 var numsMap = map[string]int{
@@ -30,15 +32,6 @@ var numsMap = map[string]int{
 	"9":     9,
 }
 
-func reverse(s string) string {
-	rns := []rune(s)
-	for i, j := 0, len(rns)-1; i < j; i, j = i+1, j-1 {
-		rns[i], rns[j] = rns[j], rns[i]
-	}
-
-	return string(rns)
-}
-
 func main() {
 	input, err := os.Open("./2023/1/input.txt")
 	if err != nil {
@@ -75,13 +68,13 @@ func main() {
 			return
 		}
 
-		lastNum := lastNumber.FindString(reverse(src))
+		lastNum := lastNumber.FindString(strmod.Reverse(src))
 		if lastNum == "" {
 			log.Printf("Failed to find last number in input string: %s", src)
 			return
 		}
 
-		hiddenNumber = numsMap[firstNum]*10 + numsMap[reverse(lastNum)]
+		hiddenNumber = numsMap[firstNum]*10 + numsMap[strmod.Reverse(lastNum)]
 		secondPartResult += hiddenNumber
 		log.Printf("Part 2: %s -> %d", src, hiddenNumber)
 	}

2023/8/main.go

@@ -9,6 +9,8 @@ import (
 	"os"
 	"regexp"
 	"strings"
+
+	"github.com/alkurbatov/adventofcode/internal/calculus"
 )
 
 var errNoNodes = errors.New("no nodes found")
@@ -85,28 +87,6 @@ func calcSteps(route []rune, from, to string, nodes map[string]Node) int {
 	}
 }
 
-// Find greatest common divisor (GCD) via Euclidean algorithm.
-func FindGCD(a, b int) int {
-	for b != 0 {
-		t := b
-		b = a % b
-		a = t
-	}
-
-	return a
-}
-
-// Find Least Common Multiple (LCM) via Greatest Common Divisor (GCD).
-func FindLCM(a, b int, values ...int) int {
-	result := a * b / FindGCD(a, b)
-
-	for i := 0; i < len(values); i++ {
-		result = FindLCM(result, values[i])
-	}
-
-	return result
-}
-
 func calcGhostSteps(route []rune, nodes map[string]Node) int {
 	steps := make([]int, 0)
 
@@ -118,7 +98,7 @@ func calcGhostSteps(route []rune, nodes map[string]Node) int {
 		steps = append(steps, calcSteps(route, from, "Z", nodes))
 	}
 
-	return FindLCM(steps[0], steps[1], steps...)
+	return calculus.FindLCM(steps...)
 }
 
 func main() {

internal/calculus/gcd.go

@@ -0,0 +1,12 @@
+package calculus
+
+// Find greatest common divisor (GCD) via Euclidean algorithm.
+func FindGCD(a, b int) int {
+	for b != 0 {
+		t := b
+		b = a % b
+		a = t
+	}
+
+	return a
+}

internal/calculus/lcm.go

@@ -0,0 +1,12 @@
+package calculus
+
+// Find Least Common Multiple (LCM) via Greatest Common Divisor (GCD).
+func FindLCM(values ...int) int {
+	result := values[0] * values[1] / FindGCD(values[0], values[1])
+
+	for i := 2; i < len(values); i++ {
+		result = FindLCM(result, values[i])
+	}
+
+	return result
+}

internal/strmod/reverse.go

@@ -0,0 +1,11 @@
+package strmod
+
+// Reverse string.
+func Reverse(s string) string {
+	rns := []rune(s)
+	for i, j := 0, len(rns)-1; i < j; i, j = i+1, j-1 {
+		rns[i], rns[j] = rns[j], rns[i]
+	}
+
+	return string(rns)
+}