1 files changed, 33 insertions, 0 deletions
diff --git a/aoc/2024/02/rust/src/main.rs b/aoc/2024/02/rust/src/main.rs
new file mode 100644
index 0000000..2007837
--- /dev/null
+++ b/aoc/2024/02/rust/src/main.rs
@@ -0,0 +1,33 @@
+#![feature(iter_map_windows)]
+
+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().filter(|&xs| all_safe(xs)).count();
+    let gold: usize = input.iter().filter(|&xs| drop_safe(xs)).count();
+    println!("silver: {silver}");
+    println!("gold: {gold}");
+}
+
+fn all_safe(xs: &Vec<i64>) -> bool {
+    let mut diffs = xs.iter().map_windows(|&[x, y]| y - x).peekable();
+    let dir = diffs.peek().unwrap_or(&1).signum();
+    diffs.all(|d| (1..=3).contains(&d.abs()) && d.signum() == dir)
+}
+
+fn drop_safe(xs: &Vec<i64>) -> bool {
+    (0..xs.len())
+        .map(|idx| xs.split_at(idx))
+        .any(|(left, right)| all_safe(&[left, &right[1..]].concat()))
+}