feat: day 1

Cargo.toml

@@ -24,6 +24,7 @@ test_lib = []
 # Template dependencies
 chrono = { version = "0.4.38", optional = true }
 dhat = { version = "0.3.3", optional = true }
+itertools = "0.13.0"
 pico-args = "0.5.0"
 tinyjson = "2.5.1"
 

data/examples/01.txt

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

src/bin/01.rs

@@ -0,0 +1,51 @@
+use itertools::Itertools;
+
+advent_of_code::solution!(1);
+
+fn get_lists(input: &str) -> (Vec<u32>, Vec<u32>) {
+    let numbers: Vec<u32> = input
+        .lines()
+        .flat_map(|line| line.split_whitespace().map(|x| x.parse::<u32>().unwrap()))
+        .collect();
+    let left = numbers.iter().step_by(2).map(|x| *x).collect();
+    let right = numbers.iter().skip(1).map(|x| *x).step_by(2).collect();
+
+    (left, right)
+}
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let (left, right) = get_lists(input);
+    Some(
+        left.iter()
+            .sorted()
+            .zip(right.iter().sorted())
+            .map(|(l, r)| l.abs_diff(*r))
+            .sum(),
+    )
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let (left, right) = get_lists(input);
+    Some(
+        left.iter()
+            .map(|l| l * right.iter().filter(|r| *r == l).count() as u32)
+            .sum(),
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(11));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(31));
+    }
+}