2024: move to single Rust crate

1 files changed, 33 insertions, 0 deletions

diff --git a/2024_rust/src/day3.rs b/2024_rust/src/day3.rs
new file mode 100644
index 0000000..cdcd62a
--- /dev/null
+++ b/2024_rust/src/day3.rs
@@ -0,0 +1,33 @@
+use regex::Regex;
+
+pub fn p1(input: &str) -> String {
+    let re = Regex::new(r"mul\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();
+
+    let mut result: u32 = 0;
+    for (_, [x, y]) in re.captures_iter(input).map(|cs| cs.extract()) {
+        result += x.parse::<u32>().unwrap() * y.parse::<u32>().unwrap();
+    }
+
+    result.to_string()
+}
+
+pub fn p2(input: &str) -> String {
+    let re = Regex::new(r"do\(\)|don't\(\)|mul\(([0-9]{1,3}),([0-9]{1,3})\)").unwrap();
+
+    let mut doing = true;
+    let mut result: u32 = 0;
+    for cs in re.captures_iter(input) {
+        let mut it = cs.iter().flatten().map(|m| m.as_str());
+        match it.next().unwrap() {
+            "do()" => doing = true,
+            "don't()" => doing = false,
+            mul if doing && mul.starts_with("mul") => {
+                let mut next = || it.next().unwrap().parse::<u32>().unwrap();
+                result += next() * next();
+            }
+            _ => (),
+        }
+    }
+
+    result.to_string()
+}