flowers field improved

rust/flower-field/src/lib.rs

@@ -1,30 +1,22 @@
-pub enum Cell {
-    Some(u32),
-    Flower,
-    None,
-}
-
 pub trait NeighbourCounter {
-    fn count_neighbours(&self, x: usize, y: usize) -> u8;
+    fn place_cell(&self, x: usize, y: usize) -> char;
 }
 
 impl NeighbourCounter for [&str] {
-    fn count_neighbours(&self, y: usize, x: usize) -> u8 {
+    fn place_cell(&self, x: usize, y: usize) -> char {
-        if 0 == self.len() {
+        if b'*' == self[y].as_bytes()[x] {
-            return 0;
+            return '*';
+        };
+        let count = (y.saturating_sub(1)..=(y + 1).min(self.len() - 1))
+            .flat_map(|ny| {
+                (x.saturating_sub(1)..=(x + 1).min(self[0].len() - 1)).map(move |nx| (ny, nx))
+            })
+            .filter(|&(ny, nx)| b'*' == self[ny].as_bytes()[nx])
+            .count();
+        match count {
+            0 => ' ',
+            c => (b'0' + c as u8) as char,
         }
-        let mut count = 0;
-        for i in y.saturating_sub(1)..=(y + 1).min(self.len() - 1) {
-            for j in x.saturating_sub(1)..=(x + 1).min(self[0].len() - 1) {
-                if i == y && j == x {
-                    continue;
-                }
-                if b'*' == self[i].as_bytes()[j] {
-                    count += 1;
-                }
-            }
-        }
-        count
     }
 }
 
@@ -32,28 +24,11 @@ pub fn annotate(garden: &[&str]) -> Vec<String> {
     if 0 == garden.len() {
         return vec![];
     }
-    garden
+    (0..garden.len())
-        .iter()
+        .map(|y| {
-        .enumerate()
+            (0..garden[y].len())
-        .map(|(i, line)| {
+                .map(|x| garden.place_cell(x, y))
-            let new_line: String = line
+                .collect()
-                .as_bytes()
-                .iter()
-                .enumerate()
-                .map(|(j, &byte)| {
-                    if b'*' == byte {
-                        return '*';
-                    }
-
-                    let count = garden.count_neighbours(i, j);
-
-                    match count {
-                        0 => ' ',
-                        c => (b'0' + c) as char,
-                    }
-                })
-                .collect();
-            new_line
         })
         .collect()
 }

rust/flower-field/src/lib_first.rs.

@@ -0,0 +1,59 @@
+pub enum Cell {
+    Some(u32),
+    Flower,
+    None,
+}
+
+pub trait NeighbourCounter {
+    fn count_neighbours(&self, x: usize, y: usize) -> u8;
+}
+
+impl NeighbourCounter for [&str] {
+    fn count_neighbours(&self, y: usize, x: usize) -> u8 {
+        if 0 == self.len() {
+            return 0;
+        }
+        let mut count = 0;
+        for i in y.saturating_sub(1)..=(y + 1).min(self.len() - 1) {
+            for j in x.saturating_sub(1)..=(x + 1).min(self[0].len() - 1) {
+                if i == y && j == x {
+                    continue;
+                }
+                if b'*' == self[i].as_bytes()[j] {
+                    count += 1;
+                }
+            }
+        }
+        count
+    }
+}
+
+pub fn annotate(garden: &[&str]) -> Vec<String> {
+    if 0 == garden.len() {
+        return vec![];
+    }
+    garden
+        .iter()
+        .enumerate()
+        .map(|(i, line)| {
+            let new_line: String = line
+                .as_bytes()
+                .iter()
+                .enumerate()
+                .map(|(j, &byte)| {
+                    if b'*' == byte {
+                        return '*';
+                    }
+
+                    let count = garden.count_neighbours(i, j);
+
+                    match count {
+                        0 => ' ',
+                        c => (b'0' + c) as char,
+                    }
+                })
+                .collect();
+            new_line
+        })
+        .collect()
+}