Day02

2024/gareth/day02/day02.go

@@ -0,0 +1,76 @@
+package day02
+
+import (
+	"math"
+	"strconv"
+	"strings"
+)
+
+func Part1(input string) int {
+	total := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		var report []int
+		nums := strings.Fields(line)
+		for _, num := range nums {
+			intnum, _ := strconv.Atoi(num)
+			report = append(report, int(intnum))
+		}
+		if isSafe(report) {
+			total++
+		}
+	}
+	return total
+}
+
+func Part2(input string) int {
+	total := 0
+	lines := strings.Split(input, "\n")
+	for _, line := range lines {
+		var report []int
+		nums := strings.Fields(line)
+		for _, num := range nums {
+			intnum, _ := strconv.Atoi(num)
+			report = append(report, int(intnum))
+		}
+		if isSafeWithDampener(report) {
+			total++
+		}
+	}
+	return total
+}
+
+func isSafe(report []int) bool {
+	increasing := report[1] > report[0]
+	decreasing := report[1] < report[0]
+
+	for i := 1; i < len(report); i++ {
+		diff := report[i] - report[i-1]
+		absDiff := int(math.Abs(float64(diff)))
+
+		if absDiff < 1 || absDiff > 3 {
+			return false
+		}
+
+		if (diff > 0 && !increasing) || (diff < 0 && !decreasing) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func isSafeWithDampener(report []int) bool {
+	if isSafe(report) {
+		return true
+	}
+
+	for i := 0; i < len(report); i++ {
+		modifiedReport := append(report[:i], report[i+1:]...)
+		if isSafe(modifiedReport) {
+			return true
+		}
+	}
+
+	return false
+}

2024/gareth/day02/day02_test.go

@@ -0,0 +1,27 @@
+package day02
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(`7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9`)
+	assert.Equal(t, 2, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2(`7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9`)
+	assert.Equal(t, 4, r)
+}

2024/gareth/day02/poc.py

@@ -0,0 +1,45 @@
+def is_safe(report):
+    increasing = report[1] > report[0]
+    decreasing = report[1] < report[0]
+
+    for i in range(1, len(report)):
+        diff = report[i] - report[i - 1]
+        abs_diff = abs(diff)
+        if abs_diff < 1 or abs_diff > 3:
+            return False
+        if (diff > 0 and not increasing) or (diff < 0 and not decreasing):
+            return False
+
+    return True
+
+def is_safe_with_dampener(report):
+    if is_safe(report):
+        return True
+    for i in range(len(report)):
+        modified_report = report[:i] + report[i+1:]
+        if is_safe(modified_report):
+            return True
+
+    return False
+
+def read_reports_from_file(filename):
+    reports = []
+    with open(filename, 'r') as file:
+        for line in file:
+            report = list(map(int, line.split()))
+            reports.append(report)
+    return reports
+
+def main():
+    filename = 'input.txt' 
+    reports = read_reports_from_file(filename)
+
+    safe_count = 0
+    for report in reports:
+        if is_safe_with_dampener(report):
+            safe_count += 1
+
+    print("OUTPUT:", safe_count)
+
+if __name__ == "__main__":
+    main()

2024/gareth/main.go

@@ -1,13 +1,13 @@
 package main
 
 import (
-	"aoc2024/day01"
+	"aoc2024/day02"
 	"fmt"
 	"os"
 )
 
 func main() {
-	data, _ := os.ReadFile("day01/input.txt")
+	data, _ := os.ReadFile("day02/input.txt")
-	fmt.Printf("part 1: %d\n", day01.Part1(string(data)))
+	fmt.Printf("part 1: %d\n", day02.Part1(string(data)))
-	fmt.Printf("part 2: %d\n", day01.Part2(string(data)))
+	fmt.Printf("part 2: %d\n", day02.Part2(string(data)))
 }