day16: improve perf again by going to i16 positions

map dimensions fit in i16, so use those in data structures

make grid support generic position type as long as they implement to i64

utils/grid/lib.rs

@@ -63,60 +63,22 @@ impl AsCoord2d for &Coord2d {
     }
 }
 
-impl AsCoord2d for (i32, i32) {
+impl<T> AsCoord2d for (T, T)
+where
+    T: Copy + TryInto<i64>,
+    <T as TryInto<i64>>::Error: Debug,
+{
     fn to_coord(self) -> Coord2d {
         Coord2d {
-            x: self.0.into(),
-            y: self.1.into(),
+            x: self.0.try_into().unwrap(),
+            y: self.1.try_into().unwrap(),
         }
     }
     fn x(&self) -> i64 {
-        self.0.into()
+        self.0.try_into().unwrap()
     }
     fn y(&self) -> i64 {
-        self.1.into()
-    }
-}
-
-impl AsCoord2d for (i64, i64) {
-    fn to_coord(self) -> Coord2d {
-        Coord2d { x: self.0, y: self.1 }
-    }
-    fn x(&self) -> i64 {
-        self.0
-    }
-    fn y(&self) -> i64 {
-        self.1
-    }
-}
-
-impl AsCoord2d for (usize, usize) {
-    fn to_coord(self) -> Coord2d {
-        Coord2d {
-            x: self.0 as i64,
-            y: self.1 as i64,
-        }
-    }
-    fn x(&self) -> i64 {
-        self.0 as i64
-    }
-    fn y(&self) -> i64 {
-        self.1 as i64
-    }
-}
-
-impl AsCoord2d for (u64, u64) {
-    fn to_coord(self) -> Coord2d {
-        Coord2d {
-            x: self.0 as i64,
-            y: self.1 as i64,
-        }
-    }
-    fn x(&self) -> i64 {
-        self.0 as i64
-    }
-    fn y(&self) -> i64 {
-        self.1 as i64
+        self.1.try_into().unwrap()
     }
 }