Remove Grid::neighbors and Grid::neighbors_diag

Author: intrepidcoder

src/bin/day10_part1.rs

@@ -27,7 +27,9 @@ fn floodfill(map: &Grid, start: usize) -> usize {
         let next_digit = char::from_digit(digit + 1, 10).unwrap();
 
         queue.extend(
-            map.neighbors(pos)
+            map.pos(pos)
+                .neighbors(map)
+                .map(|p| p.index())
                 .filter(|&next| map[next] == next_digit)
                 .filter(|&next| {
                     let v = visited[next];

src/bin/day10_part2.rs

@@ -28,7 +28,9 @@ fn floodfill(map: &Grid, start: usize) -> usize {
         let next_digit = char::from_digit(digit + 1, 10).unwrap();
 
         queue.extend(
-            map.neighbors(pos)
+            map.pos(pos)
+                .neighbors(map)
+                .map(|p| p.index())
                 .filter(|&next| map[next] == next_digit)
                 .filter(|&next| {
                     let v = visited[next];

src/bin/day12_part1.rs

@@ -28,11 +28,15 @@ fn floodfill(map: &Grid, visited: &mut [bool], start: usize) -> usize {
         area += 1;
 
         perimeter += 4 - map
-            .neighbors(pos)
+            .pos(pos)
+            .neighbors(map)
+            .map(|p| p.index())
             .filter(|&next| map[next] == map[start])
             .count();
         queue.extend(
-            map.neighbors(pos)
+            map.pos(pos)
+                .neighbors(map)
+                .map(|p| p.index())
                 .filter(|&next| map[next] == map[start])
                 .filter(|&next| {
                     let v = visited[next];

src/grid/mod.rs

@@ -114,52 +114,6 @@ impl Grid {
             .map(|(i, _)| self.pos(i))
     }
 
-    pub fn neighbors(&self, index: usize) -> impl Neighbors {
-        let (row, col) = self.coords(index);
-        NeighborsIterOld([
-            // north
-            row.checked_sub(1)
-                .filter(|&r| self.in_bounds(r, col))
-                .map(|r| r * self.width + col),
-            // east
-            Some((row, col + 1))
-                .filter(|&(r, c)| self.in_bounds(r, c))
-                .map(|(r, c)| r * self.width + c),
-            // south
-            Some((row + 1, col))
-                .filter(|&(r, c)| self.in_bounds(r, c))
-                .map(|(r, c)| r * self.width + c),
-            // west
-            col.checked_sub(1)
-                .filter(|&c| self.in_bounds(row, c))
-                .map(|c| row * self.width + c),
-        ])
-    }
-
-    /// Returns an Iterator over the 4 diagonal neighbors of a grid location
-    pub fn neighbors_diag(&self, index: usize) -> impl NeighborsDiag {
-        let (row, col) = self.coords(index);
-        NeighborsIterOld([
-            // north east
-            row.checked_sub(1)
-                .filter(|&r| self.in_bounds(r, col + 1))
-                .map(|r| r * self.width + (col + 1)),
-            // south east
-            Some((row + 1, col + 1))
-                .filter(|&(r, c)| self.in_bounds(r, c))
-                .map(|(r, c)| r * self.width + c),
-            // south west
-            col.checked_sub(1)
-                .filter(|&c| self.in_bounds(row + 1, c))
-                .map(|c| (row + 1) * self.width + c),
-            // north west
-            row.checked_sub(1)
-                .zip(col.checked_sub(1))
-                .filter(|&(r, c)| self.in_bounds(r, c))
-                .map(|(r, c)| r * self.width + c),
-        ])
-    }
-
     pub fn pos(&self, index: usize) -> Pos {
         Pos {
             index,
@@ -292,47 +246,7 @@ impl Pos {
     }
 }
 
-pub trait Neighbors: Iterator<Item = usize> {
-    fn north(&self) -> Option<usize>;
-    fn east(&self) -> Option<usize>;
-    fn south(&self) -> Option<usize>;
-    fn west(&self) -> Option<usize>;
-}
-
-pub trait NeighborsDiag: Iterator<Item = usize> {
-    fn north_east(&self) -> Option<usize>;
-    fn south_east(&self) -> Option<usize>;
-    fn south_west(&self) -> Option<usize>;
-    fn north_west(&self) -> Option<usize>;
-}
-
 pub struct NeighborsIter([Option<Pos>; 8]);
-pub struct NeighborsIterOld([Option<usize>; 4]);
-
-impl Neighbors for NeighborsIterOld {
-    fn north(&self) -> Option<usize> {
-        self.0[0]
-    }
-
-    fn east(&self) -> Option<usize> {
-        self.0[1]
-    }
-
-    fn south(&self) -> Option<usize> {
-        self.0[2]
-    }
-
-    fn west(&self) -> Option<usize> {
-        self.0[3]
-    }
-}
-
-impl Iterator for NeighborsIterOld {
-    type Item = usize;
-    fn next(&mut self) -> Option<Self::Item> {
-        self.0.iter_mut().find_map(|opt| opt.take())
-    }
-}
 
 impl Iterator for NeighborsIter {
     type Item = Pos;
@@ -341,24 +255,6 @@ impl Iterator for NeighborsIter {
     }
 }
 
-impl NeighborsDiag for NeighborsIterOld {
-    fn north_east(&self) -> Option<usize> {
-        self.0[0]
-    }
-
-    fn south_east(&self) -> Option<usize> {
-        self.0[1]
-    }
-
-    fn south_west(&self) -> Option<usize> {
-        self.0[2]
-    }
-
-    fn north_west(&self) -> Option<usize> {
-        self.0[3]
-    }
-}
-
 #[cfg(test)]
 mod test {
     use super::*;