3 files changed, 59 insertions, 0 deletions
diff --git a/2024/02/rust/Cargo.lock b/2024/02/rust/Cargo.lock
new file mode 100644
index 0000000..f3a3299
--- /dev/null
+++ b/2024/02/rust/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "aoc_2024-02"
+version = "0.1.0"
diff --git a/2024/02/rust/Cargo.toml b/2024/02/rust/Cargo.toml
new file mode 100644
index 0000000..6030837
--- /dev/null
+++ b/2024/02/rust/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "aoc_2024-02"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/2024/02/rust/src/main.rs b/2024/02/rust/src/main.rs
new file mode 100644
index 0000000..620fe8b
--- /dev/null
+++ b/2024/02/rust/src/main.rs
@@ -0,0 +1,46 @@
+use std::io;
+
+fn main() {
+    let input: Vec<Vec<i64>> = io::stdin()
+        .lines()
+        .map(|line| {
+            line.unwrap()
+                .split_whitespace()
+                .map(str::parse::<i64>)
+                .collect()
+        })
+        .collect::<Result<Vec<_>, _>>()
+        .unwrap();
+
+    let silver: usize = input.iter().map(self::safe).flatten().count();
+    let gold: u64 = 0;
+    println!("silver: {silver}");
+    println!("gold: {gold}");
+}
+
+#[derive(Debug, PartialEq)]
+enum Dir {
+    Asc,
+    Desc,
+}
+
+fn safe(xs: &Vec<i64>) -> Option<Dir> {
+    let mut dirs = xs
+        .iter()
+        .zip(xs.iter().skip(1))
+        .map(|(x, y)| y - x)
+        .map(|d| match d {
+            -3..=-1 => Some(Dir::Desc),
+            1..=3 => Some(Dir::Asc),
+            _ => None,
+        })
+        .collect::<Option<Vec<Dir>>>()?
+        .into_iter();
+
+    let head = dirs.next().unwrap_or(Dir::Asc);
+    if dirs.all(|d| d == head) {
+        Some(head)
+    } else {
+        None
+    }
+}