diff --git a/src/bin/day11.rs b/src/bin/day11.rs
index b1818f4..e5e01e7 100644
--- a/src/bin/day11.rs
+++ b/src/bin/day11.rs
@@ -34,17 +34,8 @@ impl Day11 {
                         let min_x = min(x0, x1);
                         let max_x = max(x0, x1);
 
-                        for x in &self.empty_xs {
-                            if min_x < *x && *x < max_x {
-                                xd += to_add;
-                            }
-                        }
-
-                        for y in &self.empty_ys {
-                            if y0 < *y && *y < y1 {
-                                yd += to_add;
-                            }
-                        }
+                        xd += to_add * self.empty_xs.iter().filter(|&&x| min_x < x && x < max_x).count();
+                        yd += to_add * self.empty_ys.iter().filter(|&&y| y0 < y && y < y1).count();
 
                         xd + yd
                     })