Add day1 part 2

AoC_2025/src/days/day01.rs

@@ -7,15 +7,15 @@ impl Solution for Day01 {
 
     fn parse(&self, data: &str) -> Self::Input {
         data.split("\n")
-            .map(|l| {
+            .filter_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,
+                    (Some('L'), Ok(n)) => Some(-1 * n),
+                    (Some('R'), Ok(n)) => Some(n),
+                    _ => None,
                 }
             })
             .collect()
@@ -32,6 +32,23 @@ impl Solution for Day01 {
     }
 
     fn part2(&self, input: &Self::Input) -> usize {
-        0
+        input
+            .iter()
+            .fold((50, 0), |(pointer, res), x| {
+                let new_pointer = (pointer + x).rem_euclid(100);
+                let rem_x = x % 100;
+                (
+                    (pointer + x).rem_euclid(100),
+                    res + (x / 100).abs()
+                        + if (pointer != 0 && pointer + rem_x != new_pointer)
+                            || pointer + rem_x == 0
+                        {
+                            1
+                        } else {
+                            0
+                        },
+                )
+            })
+            .1 as usize
     }
 }