Day 3

Author: prevostc

.devcontainer/devcontainer.json

@@ -28,6 +28,7 @@ heapless = "0.8.0"
 itertools = "0.13.0"
 pico-args = "0.5.0"
 rayon = "1.10.0"
+regex = "1.11.1"
 tinyjson = "2.5.1"
 
 # Solution dependencies

Cargo.lock

@@ -13,8 +13,9 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 | :---: | :---: | :---:  |
 | [Day 1](./src/bin/01.rs) | `66.9µs` | `82.5µs` |
 | [Day 2](./src/bin/02.rs) | `128.2µs` | `224.5µs` |
+| [Day 3](./src/bin/03.rs) | `688.6µs` | `810.4µs` |
 
-**Total: 0.50ms**
+**Total: 2.00ms**
 <!--- benchmarking table --->
 
 ---

Cargo.toml

@@ -0,0 +1 @@
+xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))

README.md

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))

data/examples/03-1.txt

@@ -0,0 +1,62 @@
+advent_of_code::solution!(3);
+
+use regex::Regex;
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let regex = Regex::new(r"mul\((?P<x>\d{1,3}),(?P<y>\d{1,3})\)").unwrap();
+    let sum = regex
+        .captures_iter(input)
+        .map(|captures| {
+            let x = &captures["x"].parse::<u32>().unwrap();
+            let y = &captures["y"].parse::<u32>().unwrap();
+            x * y
+        })
+        .sum();
+    Some(sum)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let regex =
+        Regex::new(r"((?P<op>do\(\)|don't\(\))|(mul\((?P<x>\d{1,3}),(?P<y>\d{1,3})\)))").unwrap();
+    let (_, sum) = regex
+        .captures_iter(input)
+        .fold((true, 0), |(on, sum), captures| {
+            if let Some(op) = captures.name("op") {
+                if op.as_str() == "don't()" {
+                    (false, sum)
+                } else if op.as_str() == "do()" {
+                    (true, sum)
+                } else {
+                    panic!("Unknown op: {}", op.as_str());
+                }
+            } else if on {
+                let x = &captures["x"].parse::<u32>().unwrap();
+                let y = &captures["y"].parse::<u32>().unwrap();
+                (true, sum + x * y)
+            } else {
+                (false, sum)
+            }
+        });
+    Some(sum)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file_part(
+            "examples", DAY, 1,
+        ));
+        assert_eq!(result, Some(161));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file_part(
+            "examples", DAY, 2,
+        ));
+        assert_eq!(result, Some(48));
+    }
+}