added input downloader

.gitignore

@@ -3,3 +3,5 @@
 
 # Ignore Gradle build output directory
 build
+
+.env

app/build.gradle.kts

@@ -29,6 +29,8 @@ dependencies {
 
     // This dependency is used by the application.
     implementation(libs.guava)
+
+    implementation("io.github.cdimascio:dotenv-kotlin:6.4.2")
 }
 
 // Apply a specific Java toolchain to ease working on different environments.

app/src/main/kotlin/day01/Day01.kt

@@ -6,44 +6,36 @@ import kotlin.math.abs
 
 class Day01 {
     fun parse(input: String): List<List<Int>> {
-        val lhs: MutableList<Int> = mutableListOf()
-        val rhs: MutableList<Int> = mutableListOf()
+        val leftList: MutableList<Int> = mutableListOf()
+        val rightList: MutableList<Int> = mutableListOf()
 
         for (line in input.lines()) {
             val split = line.split("   ").map { str -> str.toInt() }
-            lhs.add(split[0])
-            rhs.add(split[1])
+            leftList.add(split[0])
+            rightList.add(split[1])
         }
 
-        return listOf(lhs, rhs)
+        return listOf(leftList, rightList)
     }
 
     fun part1(input: String): Int {
-        val lists = parse(input)
-        val lhs = lists[0].sorted()
-        val rhs = lists[1].sorted()
+        val (leftList, rightList) = parse(input).map { list -> list.sorted() }
 
-        var sum = 0
-        for (i in 0..<lhs.count()) {
-            sum += abs(lhs[i] - rhs[i])
-        }
-        return sum;
+        return leftList.zip(rightList).map { (lhs, rhs) -> abs(lhs - rhs) }.sum()
     }
 
     fun part2(input: String): Int {
-        val lists = parse(input)
-        val lhs = lists[0].sorted()
-        val rhs = lists[1].sorted()
+        val (leftList, rightList) = parse(input).map { list -> list.sorted() }
 
         var sum = 0
-        for (i in 0..<lhs.count()) {
+        for (i in 0..<leftList.count()) {
             var rhs_idx = 0
-            val target = lhs[i]
+            val target = leftList[i]
             var count = 0
-            while (rhs[rhs_idx] < target) {
+            while (rightList[rhs_idx] < target) {
                 rhs_idx += 1
             }
-            while (rhs[rhs_idx] == target) {
+            while (rightList[rhs_idx] == target) {
                 count += 1
                 rhs_idx += 1
             }

app/src/test/kotlin/day01/Day01Test.kt

@@ -1,36 +1,42 @@
 package day01
 
 import kotlin.test.Test
-import kotlin.test.assertNotNull
-import kotlin.test.assertIs
+import util.InputDownloader
 
 class Day01Test {
-    @Test fun part1() {
-        val day = Day01()
-        val test = """3   4
-4   3
-2   5
-1   3
-3   9
-3   3"""
+    val day = 1
 
-        val output = day.part1(test)
-        println(output)
-        assert(output == 11)
+    val input = InputDownloader().getInput(day)
+    val example = InputDownloader().getExample(day)
+
+    @Test fun part1Example() {
+        part1(example, 11)
     }
 
-    @Test fun part2() {
+    @Test fun part2Example() {
+        part2(example, 31)
+    }
+
+    @Test fun part1Solution() {
+        part1(input, 1189304)
+    }
+
+    @Test fun part2Solution() {
+        part2(input, 24349736)
+    }
+
+
+    fun part1(input: String, expected: Int) {
         val day = Day01()
+        val output = day.part1(input)
+        println("output: $output")
+        assert(output == expected)
+    }
 
-        val test =  """3   4
-4   3
-2   5
-1   3
-3   9
-3   3"""
-
-        val output = day.part2(test)
-        println(output)
-        assert(output == 31)
+    fun part2(input: String, expected: Int) {
+        val day = Day01()
+        val output = day.part2(input)
+        println("output: $output")
+        assert(output == expected)
     }
 }

app/src/test/kotlin/util/InputDownloader.kt

@@ -0,0 +1,64 @@
+package util
+
+import java.net.URI
+import java.net.http.HttpClient
+import java.net.http.HttpRequest
+import java.net.http.HttpResponse
+import java.net.HttpCookie
+import java.net.CookieHandler
+import java.net.CookieManager
+import java.net.ConnectException
+import java.time.Duration
+import io.github.cdimascio.dotenv.dotenv
+
+class InputDownloader {
+    fun getInput(day: Int): String {
+        val dotenv = dotenv()
+        val sessionCookie = HttpCookie("session", dotenv["AOC_TOKEN"]);
+        sessionCookie.path = "/"
+        sessionCookie.version = 0
+
+        val manager = CookieManager()
+        manager.getCookieStore().add(URI("https://adventofcode.com"), sessionCookie)
+
+        val client = HttpClient.newBuilder()
+            .cookieHandler(manager)
+            .connectTimeout(Duration.ofSeconds(10))
+            .build()
+
+        val request = HttpRequest.newBuilder()
+            .uri(URI.create("https://adventofcode.com/2024/day/$day/input"))
+            .GET()
+            .build()
+
+        val res = client.send(request, HttpResponse.BodyHandlers.ofString())
+        if (res.statusCode() == 403) {
+            throw ConnectException("Failed to download input for day $day. Is your session token correct?")
+        }
+        if (res.statusCode() != ) {
+            throw ConnectException("Failed to download input for day $day. Is the day open yet?")
+        }
+
+        return res.body().trim()
+    }
+
+    fun getExample(day: Int): String {
+        val client = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(10)).build()
+
+        val req = HttpRequest.newBuilder()
+            .uri(URI("https://adventofcode.com/2024/day/$day"))
+            .GET()
+            .build()
+
+        val res = client.send(req, HttpResponse.BodyHandlers.ofString())
+        if (res.statusCode() != 200) {
+            throw ConnectException("Failed to download example for day $day. Is the day open yet?")
+        }
+
+        val bod = res.body()
+        val start = bod.indexOf("<pre><code>")
+        val stop = bod.indexOf("</code></pre>")
+        val sliced = bod.substring(start + 11..<stop)
+        return sliced.trim()
+    }
+}