3 files changed, 55 insertions, 0 deletions
diff --git a/2025/03/rust/Cargo.lock b/2025/03/rust/Cargo.lock
new file mode 100644
index 0000000..7f2fe0f
--- /dev/null
+++ b/2025/03/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_2025-03"
+version = "0.1.0"
diff --git a/2025/03/rust/Cargo.toml b/2025/03/rust/Cargo.toml
new file mode 100644
index 0000000..c0441da
--- /dev/null
+++ b/2025/03/rust/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "aoc_2025-03"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/2025/03/rust/src/main.rs b/2025/03/rust/src/main.rs
new file mode 100644
index 0000000..be0b3e6
--- /dev/null
+++ b/2025/03/rust/src/main.rs
@@ -0,0 +1,42 @@
+use std::io;
+
+fn max(bs: &Vec<u8>, start: usize, end: usize) -> (u8, usize) {
+    let mut bests = [None; 10];
+    for idx in start..=end {
+        if bs[idx] == 9 {
+            return (9, idx);
+        }
+        bests[bs[idx] as usize].get_or_insert((bs[idx], idx));
+    }
+    bests.into_iter().flatten().last().unwrap()
+}
+
+fn jolt(bs: &Vec<u8>, n: usize) -> u64 {
+    let mut j: u64 = 0;
+    let mut start = 0;
+    for n in (1..=n).rev() {
+        j *= 10;
+        let (b, idx) = max(bs, start, bs.len() - n);
+        j += b as u64;
+        start = idx + 1;
+    }
+    j
+}
+
+fn main() {
+    let (silver, gold) = io::stdin()
+        .lines()
+        .flatten()
+        .map(|line| {
+            line.into_bytes()
+                .iter()
+                .map(|&x| x - b'0')
+                .collect::<Vec<u8>>()
+        })
+        .map(|bs| (jolt(&bs, 2), jolt(&bs, 12)))
+        .reduce(|(a0, a1), (x0, x1)| (a0 + x0, a1 + x1))
+        .unwrap();
+
+    println!("silver: {silver}");
+    println!("gold: {gold}");
+}