day 01

Cargo.toml

@@ -14,4 +14,6 @@ doctest = false
 test_lib = []
 
 [dependencies]
+itertools = "0.12.0"
 pico-args = "0.5.0"
+regex = "1.10.2"

src/bin/01.rs

@@ -0,0 +1,54 @@
+advent_of_code::solution!(1);
+
+use itertools::Itertools;
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let result = input
+        .lines()
+        .map(|line| line.chars().filter(|&c| c.is_numeric()).collect::<String>())
+        .filter(|line| line.len() >= 1)
+        .map(|line| {
+            line.chars().nth(0).unwrap().to_digit(10).unwrap() * 10
+                + line.chars().last().unwrap().to_digit(10).unwrap()
+        })
+        .sum();
+    Some(result)
+}
+
+// list of written out numbers
+const NUMBERS: [&str; 10] = [
+    "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine",
+];
+
+#[allow(unused_variables)]
+pub fn part_two(input: &str) -> Option<u32> {
+    let res = input
+        .lines()
+        // recursively replace all written out numbers with their digits
+        .map(|line| {
+            let mut line = line.to_string();
+            for (i, number) in NUMBERS.iter().enumerate() {
+                line = line.replace(number, format!("{}{}{}", number, i, number).as_str());
+            }
+            line
+        })
+        .join("\n");
+    part_one(&res)
+}
+
+#[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(142));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_filepath("examples", "01-b"));
+        assert_eq!(result, Some(281));
+    }
+}

src/template/mod.rs

@@ -19,6 +19,16 @@ pub fn read_file(folder: &str, day: Day) -> String {
     f.expect("could not open input file")
 }
 
+pub fn read_filepath(folder: &str, filename: &str) -> String {
+    let cwd = env::current_dir().unwrap();
+    let filepath = cwd
+        .join("data")
+        .join(folder)
+        .join(format!("{filename}.txt"));
+    let f = fs::read_to_string(filepath);
+    f.expect("could not open input file")
+}
+
 /// Creates the constant `DAY` and sets up the input and runner for each part.
 #[macro_export]
 macro_rules! solution {