Day 2

1-alt/aoc01.scala

@@ -0,0 +1,10 @@
+def main(args: Array[String]): Unit = {
+  val data: Seq[Int] = io.Source.fromFile("input.txt").getLines.filter(_.nonEmpty).map(_.toInt).toSeq
+  def solution(xs: Seq[Int]): Int = xs.sliding(2, 1).count{case Seq(a, b) => b > a}
+
+  val part1 = solution(data)
+  val part2 = solution(data.sliding(3, 1).map(_.sum).toSeq)
+
+  println(s"Part 1: $part1")
+  println(s"Part 2: $part2")
+}

1-alt/run.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+nix-shell \
+  -p scala curl \
+  --run \
+  'scala -e "$(curl https://gist.githubusercontent.com/machisuji/7bca405fac2612c5a9575c056204f773/raw/b7556120bfadd9faf2b2a91ce1907df9fca2cf66/aoc01.scala); main(Array[String]());"'

2/Cargo.lock

@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "aoc-2020-1"
+version = "0.1.0"

2/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "aoc-2020-1"
+version = "0.1.0"
+authors = ["Benjamin Bädorf <hello@benjaminbaedorf.eu>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2/src/main.rs

@@ -0,0 +1,44 @@
+use std::fs;
+
+fn main() {
+    // part_1();
+    part_2();
+}
+
+fn part_1() {
+    let contents = fs::read_to_string("./input").expect("Couldn't read file!");
+    let position = contents
+        .lines()
+        .map(|s| {
+            let c: Vec<&str> = s.split(" ").collect();
+            let num = c[1].parse::<usize>().unwrap();
+            return (c[0].to_string(), num);
+        })
+        .fold((0, 0), |acc, command| match command.0.as_str() {
+            "forward" => (acc.0 + command.1, acc.1),
+            "up" => (acc.0, acc.1 - command.1),
+            "down" => (acc.0, acc.1 + command.1),
+            _ => acc,
+        });
+
+    println!("{}", position.0 * position.1);
+}
+
+fn part_2() {
+    let contents = fs::read_to_string("./input").expect("Couldn't read file!");
+    let position = contents
+        .lines()
+        .map(|s| {
+            let c: Vec<&str> = s.split(" ").collect();
+            let num = c[1].parse::<usize>().unwrap();
+            return (c[0].to_string(), num);
+        })
+        .fold((0, 0, 0), |acc, command| match command.0.as_str() {
+            "forward" => (acc.0 + command.1, acc.1, acc.2 + acc.1 * command.1),
+            "up" => (acc.0, acc.1 - command.1, acc.2),
+            "down" => (acc.0, acc.1 + command.1, acc.2),
+            _ => acc,
+        });
+
+    println!("{}", position.0 * position.2);
+}

shell.nix

@@ -3,5 +3,6 @@
 pkgs.mkShell {
   buildInputs = [
     pkgs.rustup
+    pkgs.scala
   ];
 }