diff --git a/day15/day15.go b/day15/day15.go
index f3e48fd..5d005ce 100644
--- a/day15/day15.go
+++ b/day15/day15.go
@@ -1,6 +1,11 @@
 package day15
 
-import "strconv"
+import (
+	"strconv"
+	"strings"
+
+	"gitea.paas.celticinfo.fr/oabrivard/aoc2023/utils"
+)
 
 func hash(bytes []byte) int {
 	val := 0
@@ -169,3 +174,20 @@ func SumBoxes(line string) int {
 
 	return sum
 }
+
+func Hash(bytes []byte) int {
+	return utils.Reduce(bytes, 0, func(acc int, curr byte) int {
+		return (acc + int(curr)) * 17 % 256
+	})
+}
+
+func Part1(line string) int {
+	/*
+		fmt.Println(utils.Reduce(
+			utils.Map(strings.Split(line, ","), func(step string) int { return Hash([]byte(step)) }),
+			0,
+			func(acc int, curr int) int { return acc + curr }))
+	*/
+	hashes := utils.Map(strings.Split(line, ","), func(step string) int { return Hash([]byte(step)) })
+	return utils.Reduce(hashes, 0, func(acc int, curr int) int { return acc + curr })
+}
diff --git a/day15/day15_test.go b/day15/day15_test.go
index 9b22f89..c762ca0 100644
--- a/day15/day15_test.go
+++ b/day15/day15_test.go
@@ -73,3 +73,13 @@ func TestSumBoxesWithInput(t *testing.T) {
 		t.Fatalf("expected 290779, got %v", result)
 	}
 }
+
+func TestPart1WithInput(t *testing.T) {
+	lines := utils.ReadLines("input.txt")
+
+	result := Part1(lines[0])
+
+	if result != 511416 {
+		t.Fatalf("expected 511416, got %v", result)
+	}
+}
diff --git a/utils/utils.go b/utils/utils.go
index cc62d44..bc59dea 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -175,3 +175,19 @@ func RotateClockwise[T any](slice [][]T) [][]T {
 	}
 	return result
 }
+
+func Reduce[T, M any](s []T, initValue M, f func(M, T) M) M {
+	acc := initValue
+	for _, v := range s {
+		acc = f(acc, v)
+	}
+	return acc
+}
+
+func Map[T, M any](s []T, f func(T) M) []M {
+	res := []M{}
+	for _, v := range s {
+		res = append(res, f(v))
+	}
+	return res
+}