From 39f1e7ae748642d2b9a9d543a92b2463906331e9 Mon Sep 17 00:00:00 2001
From: Sebastian Mark <smark@posteo.net>
Date: Mon, 2 Dec 2024 18:19:40 +0100
Subject: [PATCH] update day2

rewrite all functions to methods
---
 2024/02/main.go      | 117 +++++++++++++++++++++----------------------
 2024/helper/input.go |   2 +-
 2 files changed, 59 insertions(+), 60 deletions(-)

diff --git a/2024/02/main.go b/2024/02/main.go
index e8fe919..ae2a1f8 100644
--- a/2024/02/main.go
+++ b/2024/02/main.go
@@ -6,15 +6,22 @@ import (
 	"sort"
 )
 
-var reports [][]int
+type reports []report
+type report struct {
+	levels []int
+}
 
 func main() {
-	reports = helper.ReadLinesToIntArrays()
+	// generate reports
+	var reports reports
+	for _, val := range helper.ReadLinesToIntSlices() {
+		reports = append(reports, report{levels: val})
+	}
 
 	// part 1
 	save_count := 0
 	for _, r := range reports {
-		if isReportSave(r) {
+		if r.isSave() {
 			save_count++
 		}
 	}
@@ -23,23 +30,60 @@ func main() {
 	// part 2
 	save_count = 0
 	for _, r := range reports {
-		if isReportSaveWithDamper(r) {
+		if r.isSaveWithDamper() {
 			save_count++
 		}
 	}
 	fmt.Printf("Save reports (with damper): %d\n", save_count)
 }
 
-func isReportSaveWithDamper(report []int) bool {
+func (r report) isSave() bool {
+	if !r.isSorted() {
+		return false
+	}
 
-	if isReportSave(report) {
+	for i := 0; i < len(r.levels)-1; i++ {
+		if !isValidLevelDifference(r.levels[i], r.levels[i+1]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func (r report) isSorted() bool {
+	ascSorted := sort.SliceIsSorted(
+		r.levels,
+		func(i, j int) bool { return r.levels[i] < r.levels[j] },
+	)
+	descSorted := sort.SliceIsSorted(
+		r.levels,
+		func(i, j int) bool { return r.levels[i] > r.levels[j] },
+	)
+
+	return ascSorted || descSorted
+}
+
+func isValidLevelDifference(i int, j int) bool {
+	if i == j {
+		return false
+	}
+
+	if helper.Abs(i-j) > 3 {
+		return false
+	}
+
+	return true
+}
+
+func (r report) isSaveWithDamper() bool {
+	if r.isSave() {
 		return true
 	}
 
-	for i := range report {
+	for i := range r.levels {
 		// remove one item from report and try to validate
-		new_report := removeFromSlice(report, i)
-		if isReportSave(new_report) {
+		if r.removeLevelByIndex(i).isSave() {
 			return true
 		}
 	}
@@ -47,55 +91,10 @@ func isReportSaveWithDamper(report []int) bool {
 	return false
 }
 
-func removeFromSlice(slice []int, dropIndex int) []int {
-	var newslice []int
-	for i, v := range slice {
-		if i != dropIndex {
-			newslice = append(newslice, v)
-		}
-	}
+func (r report) removeLevelByIndex(dropIndex int) report {
+	var newlevels []int
+	newlevels = append(newlevels, r.levels[:dropIndex]...)
+	newlevels = append(newlevels, r.levels[dropIndex+1:]...)
 
-	return newslice
-}
-
-func isReportSave(report []int) bool {
-
-	if !isReportSorted(report) {
-		return false
-	}
-
-	for i := range report {
-		if (i + 1) < len(report) {
-			if !isPairSave(report[i], report[i+1]) {
-				return false
-			}
-		}
-	}
-
-	return true
-}
-
-func isReportSorted(slice []int) bool {
-	ascSorted := sort.SliceIsSorted(
-		slice,
-		func(i, j int) bool { return slice[i] < slice[j] },
-	)
-	descSorted := sort.SliceIsSorted(
-		slice,
-		func(i, j int) bool { return slice[i] > slice[j] },
-	)
-
-	return ascSorted || descSorted
-
-}
-
-func isPairSave(x int, y int) bool {
-	if x == y {
-		return false
-	}
-	diff := helper.Abs(x - y)
-	if diff > 3 {
-		return false
-	}
-	return true
+	return report{levels: newlevels}
 }
diff --git a/2024/helper/input.go b/2024/helper/input.go
index 6e00835..fe70669 100644
--- a/2024/helper/input.go
+++ b/2024/helper/input.go
@@ -38,7 +38,7 @@ func ReadLinesTwoIntSlices() (list_a []int, list_b []int) {
 	return list_a, list_b
 }
 
-func ReadLinesToIntArrays() (lines [][]int) {
+func ReadLinesToIntSlices() (lines [][]int) {
 	scanner := GetLines()
 	for scanner.Scan() {
 		string_line := strings.Fields(scanner.Text())