feat: completed day 2 for advent of code 2025

2025/cmd/root.go

@@ -10,10 +10,12 @@ import (
 	"github.com/spf13/cobra"
 
 	"cpatino.com/advent-of-code/2025/day01"
+	"cpatino.com/advent-of-code/2025/day03"
 )
 
 var days = map[int]func(string) (any, any){
 	1: day01.Run,
+	3: day03.Run,
 }
 
 var rootCmd = &cobra.Command{

2025/day02/day02.go

@@ -0,0 +1,123 @@
+package day02
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func Part1(input string) int {
+	total := 0
+	input = strings.TrimSpace(input)
+	if input == "" {
+		return 0
+	}
+
+	for _, rng := range strings.Split(input, ",") {
+		rng = strings.TrimSpace(rng)
+		if rng == "" {
+			continue
+		}
+
+		parts := strings.Split(rng, "-")
+		if len(parts) != 2 {
+			continue
+		}
+
+		start, end := 0, 0
+		_, err1 := fmt.Sscanf(parts[0], "%d", &start)
+		_, err2 := fmt.Sscanf(parts[1], "%d", &end)
+		if err1 != nil || err2 != nil {
+			continue
+		}
+
+		for id := start; id <= end; id++ {
+			idStr := fmt.Sprintf("%d", id)
+			for k := 1; k <= len(idStr)/2; k++ {
+				if len(idStr) == 2*k && idStr[:k] == idStr[k:] {
+					total += id
+					break
+				}
+			}
+
+		}
+	}
+
+	return total
+}
+
+func Part2(input string) int {
+	total := 0
+	input = strings.TrimSpace(input)
+	if input == "" {
+		return 0
+	}
+
+	for _, rng := range strings.Split(input, ",") {
+		rng = strings.TrimSpace(rng)
+		if rng == "" {
+			continue
+		}
+
+		parts := strings.Split(rng, "-")
+		if len(parts) != 2 {
+			continue
+		}
+
+		start, end := 0, 0
+		_, err1 := fmt.Sscanf(parts[0], "%d", &start)
+		_, err2 := fmt.Sscanf(parts[1], "%d", &end)
+		if err1 != nil || err2 != nil {
+			continue
+		}
+
+		for id := start; id <= end; id++ {
+			idStr := fmt.Sprintf("%d", id)
+			for k := 1; k <= len(idStr)/2; k++ {
+				if len(idStr)%k != 0 {
+					continue
+				}
+
+				chunk := idStr[:k]
+				valid := true
+				for i := k; i < len(idStr); i += k {
+					if idStr[i:i+k] != chunk {
+						valid = false
+						break
+					}
+				}
+
+				if valid && len(idStr)/k >= 2 {
+					total += id
+					break
+				}
+			}
+		}
+	}
+	return total
+}
+
+func Run(filename string) (any, any) {
+	file, err := os.Open(filename)
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	var lines []string
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	input := strings.Join(lines, "")
+
+	if err := scanner.Err(); err != nil {
+		panic(err)
+	}
+
+	part1 := Part1(input)
+	part2 := Part2(input)
+
+	return part1, part2
+}

2025/day02/day02_test.go

@@ -0,0 +1,34 @@
+package day02
+
+import (
+	"os"
+	"testing"
+)
+
+type TestCase struct {
+	FileName string
+	Part1    any
+	Part2    any
+}
+
+func TestDay02(t *testing.T) {
+	tests := []TestCase{
+		{"test.txt", 1227775554, 4174379265},
+		{"input.txt", 40398804950, 65794984339},
+	}
+
+	for _, test := range tests {
+		if _, err := os.Stat(test.FileName); os.IsNotExist(err) {
+			t.Fatalf("test file does not exist: %v", test.FileName)
+		}
+
+		part1, part2 := Run(test.FileName)
+		if test.Part1 != nil && part1 != test.Part1 {
+			t.Fatalf("%s: unexpected part1:\nwant:\t%v\ngot:\t%v", test.FileName, test.Part1, part1)
+		}
+
+		if test.Part2 != nil && part2 != test.Part2 {
+			t.Fatalf("%s: unexpected part2:\nwant:\t%v\ngot:\t%v", test.FileName, test.Part2, part2)
+		}
+	}
+}

2025/day02/test.txt

@@ -0,0 +1,3 @@
+11-22,95-115,998-1012,1188511880-1188511890,222220-222224,
+1698522-1698528,446443-446449,38593856-38593862,565653-565659,
+824824821-824824827,2121212118-2121212124