day 1

.gitignore

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+input.txt
+target/

day-01/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day-01"
+version = "0.1.0"

day-01/Cargo.toml

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+[package]
+name = "day-01"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

day-01/src/main.rs

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+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);
+}