day 03 part 2

aoc2023/src/day03.rs

@@ -51,14 +51,39 @@ impl Solution for Day03 {
 
         let mut out: u64 = 0;
 
+        let gear = Regex::new(r"\*").unwrap();
+        let num = Regex::new(r"\d+").unwrap();
+
         for (i, line) in lines.iter().enumerate() {
+            for star in gear.find_iter(line) {
+                let prev = if i > 0 { lines.get(i - 1) } else { None };
+                let curr = lines.get(i);
+                let next = lines.get(i+1);
 
+                let mut nums: Vec<u64> = vec![];
+
+                if prev != None {
+                    for number in num.find_iter(prev.unwrap()) {
+                        if ((1.max(number.start())-1)..(number.end()+1)).contains(&star.start()) { nums.push(number.as_str().parse().unwrap()) }
+                    }
+                }
+                if curr != None {
+                    for number in num.find_iter(curr.unwrap()) {
+                        if ((1.max(number.start())-1)..(number.end()+1)).contains(&star.start()) { nums.push(number.as_str().parse().unwrap()) }
+                    }
+                }
+                if next != None {
+                    for number in num.find_iter(next.unwrap()) {
+                        if ((1.max(number.start())-1)..(number.end()+1)).contains(&star.start()) { nums.push(number.as_str().parse().unwrap()) }
+                    }
                 }
 
-        Answer::Unimplemented
+                if nums.len() == 2 {
+                    out += nums[0] * nums[1]
+                }
+            }
+        }
+
+        Answer::from(out)
     }
 }
-
-fn extract_num(line: &str, pos: usize) -> u64 {
-    todo!()
-}

src/main.rs

@@ -11,7 +11,7 @@ fn main() {
     let Ok(data) = load_actual(2023, 3)
         else { return; };
 
-    let result = aoc2023::day03::Day03.part_1(&data);
+    let result = aoc2023::day03::Day03.part_2(&data);
 
     let elapsed = now.elapsed();