Day 3

src/day3.rs

@@ -0,0 +1,23 @@
+use std::fs;
+use regex::Regex;
+
+const READ_ALL: bool = false;
+
+pub fn day3() {
+    let input_text = fs::read_to_string("res/puzzle_3.txt").unwrap();
+
+    let mut total: u64 = 0;
+    let mut enabled = true;
+    for statement in Regex::new(r"(?:mul\((?<a>\d{1,3}),(?<b>\d{1,3})\))|(?<do>do\(\))|(?<dont>don't\(\))").unwrap().captures_iter(&input_text) {
+        if statement.name("do").is_some() {
+            enabled = true;
+        } else if statement.name("dont").is_some() {
+            enabled = false;
+        } else if enabled || READ_ALL {
+            let numbers: Vec<u64> = vec![&statement["a"], &statement["b"]].iter().map(|s| s.parse::<u64>().unwrap()).collect();
+            total += numbers[0] * numbers[1];
+        }
+    }
+
+    println!("Total: {}", total);
+}

src/main.rs

@@ -1,6 +1,7 @@
 mod day1;
 mod day2;
+mod day3;
 
 fn main() {
-    day2::day2();
+    day3::day3();
 }