day 01

.gitignore

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+# Created by https://www.toptal.com/developers/gitignore/api/goland+all,go,linux
+# Edit at https://www.toptal.com/developers/gitignore?templates=goland+all,go,linux
+
+### Go ###
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+### GoLand+all ###
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+
+# AWS User-specific
+.idea/**/aws.xml
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/artifacts
+# .idea/compiler.xml
+# .idea/jarRepositories.xml
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+# *.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# SonarLint plugin
+.idea/sonarlint/
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Android studio 3.1+ serialized cache file
+.idea/caches/build_file_checksums.ser
+
+### GoLand+all Patch ###
+# Ignore everything but code style settings and run configurations
+# that are supposed to be shared within teams.
+
+.idea/*
+
+!.idea/codeStyles
+!.idea/runConfigurations
+
+### Linux ###
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+# End of https://www.toptal.com/developers/gitignore/api/goland+all,go,linux

01/go.mod

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+module adventofcode2024/01
+
+go 1.23

01/main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"math"
+	"os"
+	"regexp"
+	"sort"
+	"strconv"
+)
+
+var (
+	inputFile = flag.String("input", "input.txt", "input filename")
+	reLine    = regexp.MustCompile(`(?m)^(\d+)\s+(\d+)$`)
+)
+
+func main() {
+	flag.Parse()
+	input, err := os.ReadFile(*inputFile)
+	if err != nil {
+		panic(err)
+	}
+
+	var leftList, rightList []int
+	for _, match := range reLine.FindAllStringSubmatch(string(input), -1) {
+		leftNumber, err := strconv.Atoi(match[1])
+		if err != nil {
+			panic(err)
+		}
+
+		rightNumber, err := strconv.Atoi(match[2])
+		if err != nil {
+			panic(err)
+		}
+
+		leftList = append(leftList, leftNumber)
+		rightList = append(rightList, rightNumber)
+	}
+
+	sort.SliceStable(leftList, func(i, j int) bool {
+		return leftList[i] < leftList[j]
+	})
+	sort.SliceStable(rightList, func(i, j int) bool {
+		return rightList[i] < rightList[j]
+	})
+
+	totalDistance := 0
+	for i := 0; i < len(leftList); i++ {
+		totalDistance += int(math.Abs(float64(leftList[i] - rightList[i])))
+	}
+
+	fmt.Println(totalDistance)
+}