Add solution for 2024 day 01

2024/day-01/common.rs

@@ -0,0 +1,35 @@
+use std::fs;
+use std::path::Path;
+
+
+#[derive(Debug)]
+pub struct PuzzleInputs {
+    pub left: Vec<i32>,
+    pub right: Vec<i32>,
+}
+
+impl PuzzleInputs {
+    pub fn parse<P>(path: P) -> Self
+        where P: AsRef<Path>
+    {
+        let mut left = Vec::new();
+        let mut right = Vec::new();
+
+        let content = fs::read_to_string(path).unwrap();
+
+        for line in content.lines() {
+            let mut parts = line.split(' ');
+
+            // unwrap is very festive
+            let first = parts.next().unwrap();
+            let first = first.parse().unwrap();
+            let last = parts.last().unwrap();
+            let last = last.parse().unwrap();
+
+            left.push(first);
+            right.push(last);
+        }
+
+        Self { left, right }
+    }
+}

2024/day-01/part_one.rs

@@ -0,0 +1,22 @@
+mod common;
+
+use common::PuzzleInputs;
+
+
+const INPUT_FILE: &str = "puzzle.txt";
+
+
+fn main() {
+    let mut inputs = PuzzleInputs::parse(INPUT_FILE);
+
+    inputs.left.sort();
+    inputs.right.sort();
+
+    let mut sum = 0;
+    for (l, r) in inputs.left.into_iter().zip(inputs.right) {
+        let dist = l.abs_diff(r);
+        sum += dist;
+    }
+
+    println!("{sum}");
+}

2024/day-01/part_two.rs

@@ -0,0 +1,30 @@
+mod common;
+
+use std::collections::HashMap;
+
+use common::PuzzleInputs;
+
+type Hist = HashMap<i32, i32>;
+
+
+const INPUT_FILE: &str = "puzzle.txt";
+
+
+fn main() {
+    let inputs = PuzzleInputs::parse(INPUT_FILE);
+    let mut hist = Hist::new();
+
+    for elem in inputs.right {
+        hist.entry(elem).and_modify(|e| *e += 1).or_insert(1);
+    }
+
+    let mut score = 0;
+
+    for elem in &inputs.left {
+        if let Some(x) = hist.get(elem) {
+            score += elem * x;
+        }
+    }
+
+    println!("{score:?}");
+}

2024/day-01/sample.txt

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3