Day 1

2024/go/day1/main.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"math"
+	"os"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+func Part1(firstCol []int, secondCol []int) int {
+	slices.Sort(firstCol)
+	slices.Sort(secondCol)
+
+	sum := 0.0
+	for i := 0; i < len(firstCol); i++ {
+		sum += math.Abs(float64(firstCol[i] - secondCol[i]))
+	}
+
+	return int(sum)
+}
+
+func Part2(firstCol []int, secondCol []int) int {
+	counts := make(map[int]int)
+	for _, num := range secondCol {
+		counts[num]++
+	}
+
+	sum := 0
+	for _, num := range firstCol {
+		sum += num * counts[num]
+	}
+
+	return sum
+}
+
+func main() {
+	flag.Parse()
+
+	if len(flag.Args()) == 0 {
+		panic("Please provide a filename")
+	}
+
+	filename := flag.Args()[0]
+
+	file, err := os.Open(filename)
+	if err != nil {
+		panic(err)
+	}
+	defer file.Close()
+
+	var firstCol []int
+	var secondCol []int
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := scanner.Text()
+		words := strings.Fields(line)
+
+		var input []int
+		for _, word := range words {
+			word, err := strconv.Atoi(word)
+			if err != nil {
+				panic(err)
+			}
+
+			input = append(input, word)
+		}
+
+		firstCol = append(firstCol, input[0])
+		secondCol = append(secondCol, input[1])
+	}
+
+	answer := Part1(firstCol, secondCol)
+	fmt.Println(answer)
+
+	answer = Part2(firstCol, secondCol)
+	fmt.Println(answer)
+}

2024/go/go.mod

@@ -0,0 +1,3 @@
+module cpatino.com/2024
+
+go 1.23.3