Stage 1

AoC_2025/src/days/day01.rs

@@ -3,12 +3,32 @@ use crate::days::Solution;
 pub struct Day01;
 
 impl Solution for Day01 {
-    type Input = ();
+    type Input = Vec<i16>;
 
-    fn parse(&self, data: &str) -> Self::Input {}
+    fn parse(&self, data: &str) -> Self::Input {
+        data.split("\n")
+            .map(|l| {
+                let mut chars = l.chars();
+                let first = chars.next();
+                let num = chars.collect::<String>().parse::<i16>();
+
+                match (first, num) {
+                    (Some('L'), Ok(n)) => -1 * n,
+                    (Some('R'), Ok(n)) => n,
+                    _ => 0,
+                }
+            })
+            .collect()
+    }
 
     fn part1(&self, input: &Self::Input) -> usize {
-        0
+        input
+            .iter()
+            .fold((50, 0), |(sum, res), x| match (sum + x) % 100 {
+                0 => (0, res + 1),
+                newsum => (newsum, res),
+            })
+            .1
     }
 
     fn part2(&self, input: &Self::Input) -> usize {