commit c2575cbcea9b87444f2f04e17eb1480303230f17
Author: Aaron Manning <contact@aaronmanning.net>
Date:   Fri Dec 6 18:18:25 2024 +1100

    day 1

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..fae1e28
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+input.txt
+target/
diff --git a/day-01/Cargo.lock b/day-01/Cargo.lock
new file mode 100644
index 0000000..7dc86fc
--- /dev/null
+++ b/day-01/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day-01"
+version = "0.1.0"
diff --git a/day-01/Cargo.toml b/day-01/Cargo.toml
new file mode 100644
index 0000000..84d4d11
--- /dev/null
+++ b/day-01/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day-01"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/day-01/src/main.rs b/day-01/src/main.rs
new file mode 100644
index 0000000..f1b8b14
--- /dev/null
+++ b/day-01/src/main.rs
@@ -0,0 +1,43 @@
+const INPUT: &str = include_str!(concat!(env!("CARGO_MANIFEST_DIR"), "/input.txt"));
+
+fn main() {
+    let (mut first, mut second): (Vec<_>, Vec<_>) =
+        INPUT.lines()
+        .filter_map(|line| {
+            let mut parts = line.split_whitespace();
+            let first = parts.next()?;
+            let second = parts.next()?;
+            Some((
+                str::parse::<u32>(first).ok()?,
+                str::parse::<u32>(second).ok()?,
+            ))
+        })
+        .unzip();
+
+    first.sort();
+    second.sort();
+
+    let difference = first.iter().zip(second.iter().copied())
+        .map(|(x, y)| x.abs_diff(y))
+        .sum::<u32>();
+
+    println!("Part 1: {}", difference);
+
+    let mut similarity = 0;
+    let mut idx = 0;
+    for element in first {
+        while second.get(idx).is_some_and(|x| *x < element) {
+            idx += 1;
+        }
+
+        let mut occurances = 0;
+        while second.get(idx) == Some(&element) {
+            idx += 1;
+            occurances += 1;
+        }
+
+        similarity += occurances * element;
+    }
+
+    println!("Part 2: {}", similarity);
+}