Import helper

go.mod

@@ -0,0 +1,3 @@
+module AOC2021
+
+go 1.17

src/helper/helper.go

@@ -0,0 +1,100 @@
+package helper
+
+import (
+	"errors"
+	"io/ioutil"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+func GetInput(filename string) ([]string, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	lines := strings.Split(string(content), "\r\n")
+	return lines, err
+}
+
+func GetFile(filename string) (string, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return "", err
+	}
+	return string(content), err
+}
+
+func MapToNumber(strings []string) ([]int, error) {
+	var numbers []int
+	for _, line := range strings {
+		number, err := strconv.Atoi(line)
+		if err != nil {
+			return numbers, err
+		}
+		numbers = append(numbers, number)
+	}
+	return numbers, nil
+}
+
+func FindAddendsForSum(possibleAddends []int, sum int) (int, int, error) {
+	var array = make([]int, len(possibleAddends))
+	copy(array, possibleAddends)
+	sort.Ints(array)
+	p1 := 0
+	p2 := len(array) - 1
+	for p1 < p2 {
+		if array[p1]+array[p2] < sum {
+			p1++
+		}
+		if array[p1]+array[p2] > sum {
+			p2--
+		}
+		if array[p1]+array[p2] == sum {
+			return array[p1], array[p2], nil
+		}
+	}
+	return 0, 0, errors.New("No fitting Addends found")
+}
+
+func SliceIndex(limit int, predicate func(i int) bool) int {
+	for i := 0; i < limit; i++ {
+		if predicate(i) {
+			return i
+		}
+	}
+	return -1
+}
+
+func DeleteAt(a []int, i int, ) []int {
+	return append(a[:i], a[i+1:]...)
+}
+
+func Equal(a, b []int) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, v := range a {
+		if v != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
+func Contains(elem int, array []int) bool{
+	for _, val := range array{
+		if val == elem{
+			return true
+		}
+	}
+	return false
+}
+
+func AddNummbers(numbers ...int) int {
+	result := 0
+	for _, number := range numbers {
+		result += number
+	}
+	return result
+}