working 15part2, but slower

src/day15/main.rs

@@ -52,6 +52,7 @@ impl Map {
 
     fn walk(&mut self, start: &XY, computer: &intcode::Computer, steps: usize) -> Option<usize> {
         let steps = steps + 1;
+        let mut result = None;
         for dir in 1..=4 {
             let direction = Direction::from(dir);
             let xy = start.add((&direction).into());
@@ -66,17 +67,17 @@ impl Map {
                 match status {
                     Status::HitWall => (),
                     Status::MoveComplete => match self.walk(&xy, &computer, steps) {
-                        Some(i) => return Some(i + 1),
+                        Some(i) => result = Some(i + 1),
                         None => (),
                     },
-                    Status::Finished => return Some(1),
+                    Status::Finished => result = Some(1),
                     _ => unreachable!("unknown status"),
                 }
             } else {
                 unreachable!("computer unexpectedly halted");
             }
         }
-        None
+        result
     }
 
     fn fill(&mut self) -> usize {