From 560e0401b0d2f0ced83e422df37980ddfe2fef4b Mon Sep 17 00:00:00 2001
From: Federico Igne <git@federicoigne.com>
Date: Thu, 2 Dec 2021 15:11:40 +0000
Subject: Day 2

---
 day2/src/main.rs | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 day2/src/main.rs

(limited to 'day2/src/main.rs')

diff --git a/day2/src/main.rs b/day2/src/main.rs
new file mode 100644
index 0000000..3748138
--- /dev/null
+++ b/day2/src/main.rs
@@ -0,0 +1,50 @@
+use std::fs;
+use std::path::Path;
+
+enum Cmd {
+    Forward(i32),
+    Depth(i32)
+}
+
+impl From<&str> for Cmd {
+    fn from(s: &str) -> Self {
+        let (cmd, amount) = s.split_once(' ').expect("Malformed input");
+        let amount = amount.parse().expect("Malformed input");
+        match cmd {
+            "down"    => Cmd::Depth(amount),
+            "up"      => Cmd::Depth(-amount),
+            "forward" => Cmd::Forward(amount),
+            _         => unreachable!("Malformed input")
+        }
+    }
+}
+
+fn ex1(route: &[Cmd]) {
+    let pos = route.iter().fold((0,0),
+        |(f,d),c| match c {
+            Cmd::Depth(a) => (f,d+a),
+            Cmd::Forward(a) => (f+a,d),
+        }
+    );
+    println!("Ex1: The result is {}", pos.0 * pos.1);
+}
+
+fn ex2(route: &[Cmd]) {
+    let pos = route.iter().fold((0,0,0),
+        |(a,f,d),c| match c {
+            Cmd::Depth(i) => (a+i,f,d),
+            Cmd::Forward(i) => (a,f+i,d+a*i),
+        }
+    );
+    println!("Ex2: The result is {}", pos.1 * pos.2);
+}
+
+/* AOC21 Day 2: https://adventofcode.com/2021/day/2 */
+fn main() {
+    let input = Path::new("resources").join("input.txt");
+    let content = fs::read_to_string(input).expect("Unable to read input file");
+    let route: Vec<Cmd> = content.lines().map( |l| Cmd::from(l)).collect();
+    ex1(&route);
+    ex2(&route);
+}
+
-- 
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