day 3: part 2: rust

2024/days/03/part2/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "part1"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+regex = "1.11.1"

2024/days/03/part2/src/main.rs

@@ -0,0 +1,26 @@
+use regex::Regex;
+
+fn main() -> std::io::Result<()> {
+    let mut sum: u32 = 0;
+    let re1 = Regex::new(r"(do\(\)|don't\(\)|mul\([0-9]*,[0-9]*\))").unwrap();
+    let re2 = Regex::new(r"mul\(([0-9]*),([0-9]*)\)").unwrap();
+    let hay = std::io::read_to_string(std::io::stdin()).unwrap();
+    let mut i_do = true;
+    for (_, [does]) in re1.captures_iter(&hay).map(|c| c.extract()) {
+        if does == "do()" {
+            i_do = true;
+        } 
+        if does == "don't()" {
+            i_do = false;
+        }
+        if i_do {
+            for (_, [num1, num2]) in re2.captures_iter(does).map(|c| c.extract()) {
+                let num1: u32 = num1.parse().unwrap();
+                let num2: u32 = num2.parse().unwrap();
+                sum += num1 * num2;
+            } 
+        }
+    }
+    println!("{}", sum);
+    Ok(())
+}