A new advent of code, day 1 finished

advent_of_code/2024/1/src/main.rs

@@ -0,0 +1,94 @@
+use std::{collections::HashMap, iter::zip};
+
+fn distance<A>(a: A, b: A) -> A
+where
+    A: std::ops::Sub<Output = A> + Ord,
+{
+    if a < b {
+        return b.sub(a);
+    } else {
+        return a.sub(b);
+    }
+}
+
+fn solve_1(input: &str) -> u32 {
+    let input: Vec<Vec<u32>> = input
+        .lines()
+        .map(|element| {
+            element
+                .split_ascii_whitespace()
+                .map(|numbers| numbers.parse::<u32>().unwrap())
+                .collect()
+        })
+        .collect();
+    // Double collect(), wowsers that's ugly but it works?
+
+    let mut left: Vec<u32> = input.iter().map(|v| v[0].to_owned()).collect();
+    let mut right: Vec<u32> = input.iter().map(|v| v[1].to_owned()).collect();
+
+    left.sort();
+    right.sort();
+
+    return zip(left, right).fold(0, |x, (l, r)| x + distance(l, r));
+}
+
+fn solve_2(input: &str) -> u32 {
+    let input: Vec<Vec<u32>> = input
+        .lines()
+        .map(|element| {
+            element
+                .split_ascii_whitespace()
+                .map(|numbers| numbers.parse::<u32>().unwrap())
+                .collect()
+        })
+        .collect();
+
+    let left: Vec<u32> = input.iter().map(|v| v[0].to_owned()).collect();
+    let right: Vec<u32> = input.iter().map(|v| v[1].to_owned()).collect();
+
+    let mut occurrences: HashMap<u32, u32> = HashMap::new();
+    for r in right.into_iter() {
+        occurrences.insert(
+            r,
+            match occurrences.get(&r) {
+                None => 1,
+                Some(v) => v + 1,
+            },
+        );
+    }
+
+    return left
+        .into_iter()
+        .fold(0, |s, l| s + l * occurrences.get(&l).unwrap_or(&0));
+}
+
+fn main() {
+    println!("Hello, this is Patrick!");
+
+    let input_text = include_str!("../input.txt");
+
+    let result_1 = solve_1(input_text);
+    println!("The total distance between the two lists is {}", result_1);
+
+    let result_2 = solve_2(input_text);
+    println!("The similarity score of the two lists is {}", result_2);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let test_input = include_str!("../test.txt");
+
+        assert_eq!(solve_1(test_input), 11);
+    }
+
+    #[test]
+    fn test_2() {
+        let test_input = include_str!("../test.txt");
+
+        assert_eq!(solve_2(test_input), 31);
+    }
+}