solve day 2

2024/day1/part1.go → 2024/day1/day1.go

@@ -1,4 +1,4 @@
-package day1_part1
+package day1
 
 import (
 	"adventofcode/utils"

2024/day2/day2.go

@@ -0,0 +1,79 @@
+package day2
+
+import (
+	"adventofcode/utils"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+)
+
+func Part1(file string) int {
+	lines := utils.ReadFileByLine(file)
+	validLine := 0
+	for _, line := range lines {
+		sNumbers := strings.Split(line, " ")
+		var numbers []int
+		for _, sn := range sNumbers {
+			num, _ := strconv.Atoi(sn)
+			numbers = append(numbers, num)
+		}
+		if Validline(numbers) {
+			validLine += 1
+		}
+	}
+	fmt.Println(validLine)
+	return validLine
+}
+
+func Part2(file string) int {
+	lines := utils.ReadFileByLine(file)
+	validLine := 0
+	for _, line := range lines {
+		sNumbers := strings.Split(line, " ")
+		var numbers []int
+		for _, sn := range sNumbers {
+			num, _ := strconv.Atoi(sn)
+			numbers = append(numbers, num)
+		}
+		valid := false
+		for i := range numbers {
+			if Validline(numbers) || Validline(RemoveIndex(numbers, i)) {
+				valid = true
+			}
+		}
+		if valid {
+			validLine += 1
+		}
+	}
+	fmt.Println(validLine)
+	return validLine
+}
+
+func Validline(line []int) bool {
+	valid := true
+	for i, num := range line {
+		if i >= len(line)-1 {
+			break
+		}
+		num2 := line[i+1]
+		dist := int(math.Abs(float64(num - num2)))
+		// check if difference is > 1 < 3
+		if dist < 1 || dist > 3 {
+			valid = false
+			break
+		}
+		// check if always increasing or decreasing
+		if (num-num2 < 0 && line[0]-line[1] > 0) || (num-num2 > 0 && line[0]-line[1] < 0) {
+			valid = false
+			break
+		}
+	}
+	return valid
+}
+
+func RemoveIndex(s []int, index int) []int {
+	ret := make([]int, 0)
+	ret = append(ret, s[:index]...)
+	return append(ret, s[index+1:]...)
+}