2 files changed, 58 insertions, 0 deletions

diff --git a/2022/day4/part2/Cargo.toml b/2022/day4/part2/Cargo.toml
new file mode 100644
index 0000000..69fa504
--- /dev/null
+++ b/2022/day4/part2/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "part2"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+itertools = "0.10.5"
diff --git a/2022/day4/part2/src/main.rs b/2022/day4/part2/src/main.rs
new file mode 100644
index 0000000..d7f378a
--- /dev/null
+++ b/2022/day4/part2/src/main.rs
@@ -0,0 +1,49 @@
+use itertools::Itertools;
+
+#[derive(Debug)]
+struct Elf {
+    start: usize,
+    end: usize,
+}
+
+#[derive(Debug)]
+struct Pair(Elf, Elf);
+
+impl Elf {
+    pub fn new(range: &str) -> Self {
+        if let Some((start, end)) = range.to_string().split("-").collect_tuple() {
+            let start: usize = start.parse().unwrap();
+            let end: usize = end.parse().unwrap();
+            Self { start, end }
+        } else {
+            panic!("Expected two elements");
+        }
+    }
+}
+
+impl Pair {
+    pub fn new(line: &str) -> Self {
+        if let Some((first, second)) = line.to_string().split(",").collect_tuple() {
+            Pair(Elf::new(first), Elf::new(second))
+        } else {
+            panic!("Expected two elements");
+        }
+    }
+}
+
+impl Pair {
+    fn overlaps(&self) -> bool {
+        !(self.0.end < self.1.start || self.1.end < self.0.start)
+    }
+}
+
+fn main() {
+    let sum: usize = include_str!("../../input")
+        .lines()
+        .map(|l| Pair::new(l))
+        .map(|p| p.overlaps())
+        .filter(|r| *r)
+        .count();
+
+    println!("{}", sum);
+}