switched to workspaces.

This should let me make a cross-day library.

days/day04/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "day04"
+authors.workspace = true
+description.workspace = true
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+once_cell.workspace = true
+regex.workspace = true

days/day04/src/main.rs

@@ -0,0 +1,14 @@
+mod part1;
+mod part2;
+mod utilities;
+
+fn main() {
+    let _input = include_str!("./input.txt");
+    let _structured_input = utilities::parse(_input);
+
+    println!("Part One");
+    println!("Result: {}", part1::part1(&_structured_input));
+
+    println!("Part Two");
+    println!("Result: {}", part2::part2(&_structured_input));
+}

days/day04/src/part1.rs

@@ -0,0 +1,27 @@
+use crate::utilities::*;
+
+pub fn part1(input: &[(Range, Range)]) -> usize {
+    input
+        .iter()
+        .filter(|tuple| tuple.0.complete_overlap(&tuple.1))
+        .count()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part1() {
+        let input = vec![
+            (Range::new(2, 4), Range::new(6, 8)),
+            (Range::new(2, 3), Range::new(4, 5)),
+            (Range::new(5, 7), Range::new(7, 9)),
+            (Range::new(2, 8), Range::new(3, 7)),
+            (Range::new(6, 6), Range::new(4, 6)),
+            (Range::new(2, 6), Range::new(4, 8)),
+            (Range::new(19, 30), Range::new(5, 18)),
+        ];
+        assert_eq!(part1(&input), 2);
+    }
+}

days/day04/src/part2.rs

@@ -0,0 +1,27 @@
+use crate::utilities::*;
+
+pub fn part2(input: &[(Range, Range)]) -> usize {
+    input
+        .iter()
+        .filter(|tuple| tuple.0.any_overlap(&tuple.1))
+        .count()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part2() {
+        let input = vec![
+            (Range::new(2, 4), Range::new(6, 8)),
+            (Range::new(2, 3), Range::new(4, 5)),
+            (Range::new(5, 7), Range::new(7, 9)),
+            (Range::new(2, 8), Range::new(3, 7)),
+            (Range::new(6, 6), Range::new(4, 6)),
+            (Range::new(2, 6), Range::new(4, 8)),
+            (Range::new(19, 30), Range::new(5, 18)),
+        ];
+        assert_eq!(part2(&input), 4);
+    }
+}

days/day04/src/utilities.rs

@@ -0,0 +1,79 @@
+use once_cell::sync::Lazy;
+use regex::Regex;
+#[derive(Debug, PartialEq, Eq)]
+pub struct Range {
+    start: u16,
+    end: u16,
+}
+
+impl Range {
+    pub fn new(start: u16, end: u16) -> Self {
+        Self {
+            start: start.min(end),
+            end: end.max(start),
+        }
+    }
+
+    pub fn any_overlap(&self, other: &Self) -> bool {
+        self.start <= other.end && self.end >= other.start
+    }
+
+    pub fn calc_overlap(&self, other: &Self) -> Range {
+        let overlap_start = self.start.min(other.start);
+        let overlap_end = self.end.max(other.end);
+        Range::new(overlap_start, overlap_end)
+    }
+
+    pub fn complete_overlap(&self, other: &Self) -> bool {
+        self.calc_overlap(other) == *self || self.calc_overlap(other) == *other
+    }
+}
+
+static PARSE_REGEX: Lazy<Regex> = Lazy::new(|| Regex::new(r"^(\d+)-(\d+),(\d+)-(\d+)").unwrap());
+
+pub fn parse(input: &str) -> Vec<(Range, Range)> {
+    input
+        .lines()
+        .map(|line| {
+            let cap = PARSE_REGEX.captures(line).unwrap();
+            (
+                Range::new(
+                    cap.get(1).unwrap().as_str().parse().unwrap(),
+                    cap.get(2).unwrap().as_str().parse().unwrap(),
+                ),
+                Range::new(
+                    cap.get(3).unwrap().as_str().parse().unwrap(),
+                    cap.get(4).unwrap().as_str().parse().unwrap(),
+                ),
+            )
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse() {
+        let input = "2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8
+19-30,5-18";
+        assert_eq!(
+            parse(input),
+            vec![
+                (Range::new(2, 4), Range::new(6, 8)),
+                (Range::new(2, 3), Range::new(4, 5)),
+                (Range::new(5, 7), Range::new(7, 9)),
+                (Range::new(2, 8), Range::new(3, 7)),
+                (Range::new(6, 6), Range::new(4, 6)),
+                (Range::new(2, 6), Range::new(4, 8)),
+                (Range::new(19, 30), Range::new(5, 18)),
+            ]
+        );
+    }
+}