From 0000005019c0faa7e3175b4a179eb34d21f0cca6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matej=20Jane=C5=BEi=C4=8D?= <janezic.mj@gmail.com>
Date: Tue, 3 Dec 2024 07:22:09 +0100
Subject: [PATCH] solution: day 3

---
 data/examples/03.txt |  1 +
 src/bin/03.rs        | 52 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 data/examples/03.txt
 create mode 100644 src/bin/03.rs

diff --git a/data/examples/03.txt b/data/examples/03.txt
new file mode 100644
index 000000000..30032cb
--- /dev/null
+++ b/data/examples/03.txt
@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))
diff --git a/src/bin/03.rs b/src/bin/03.rs
new file mode 100644
index 000000000..523f868
--- /dev/null
+++ b/src/bin/03.rs
@@ -0,0 +1,52 @@
+use regex::Regex;
+
+fn solve(input: &str, flip: bool) -> usize {
+    let r = Regex::new(r"mul\((\d+),(\d+)\)|do\(\)|don't\(\)").unwrap();
+
+    let mut enabled = true;
+    let mut res = 0;
+
+    for c in r.captures_iter(input) {
+        let full = c.get(0).unwrap().as_str();
+        match &full[..=2] {
+            "mul" => {
+                if enabled {
+                    let a: usize = c.get(1).unwrap().as_str().parse().unwrap();
+                    let b: usize = c.get(2).unwrap().as_str().parse().unwrap();
+                    res += a * b;
+                }
+            }
+            "do(" => enabled = true,
+            "don" => enabled = !flip,
+            _ => unreachable!(),
+        }
+    }
+
+    res
+}
+
+pub fn part_one(input: &str) -> Option<usize> {
+    solve(input, false).into()
+}
+
+pub fn part_two(input: &str) -> Option<usize> {
+    solve(input, true).into()
+}
+
+aoc::solution!(3);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_part_one() {
+        assert_eq!(
+            part_one(&aoc::template::read_file("examples", 3)),
+            Some(161)
+        );
+    }
+    #[test]
+    fn test_part_two() {
+        assert_eq!(part_two(&aoc::template::read_file("examples", 3)), Some(48));
+    }
+}