Update Square::Options to Marks and index at 1.

src/board.rs

@@ -27,7 +27,7 @@ impl Board {
     pub fn restrict_marks(&mut self) {
         let self_copy = self.clone();
         for (index, ref mut square) in self.squares.iter_mut().enumerate() {
-            if let Square::Options(ref mut opt) = square {
+            if let Square::Marks(ref mut marks) = square {
                 self_copy
                     .row_from_index(index)
                     .filter_map(|sq| match sq {
@@ -35,7 +35,7 @@ impl Board {
                         _ => None,
                     })
                     .for_each(|value| {
-                        opt.set((value - 1) as usize, false);
+                        marks.set(value as usize, false);
                     });
                 self_copy
                     .col_from_index(index)
@@ -44,7 +44,7 @@ impl Board {
                         _ => None,
                     })
                     .for_each(|value| {
-                        opt.set((value - 1) as usize, false);
+                        marks.set(value as usize, false);
                     });
                 self_copy
                     .box_from_index(index)
@@ -53,7 +53,7 @@ impl Board {
                         _ => None,
                     })
                     .for_each(|value| {
-                        opt.set((value - 1) as usize, false);
+                        marks.set(value as usize, false);
                     });
             }
         }
@@ -99,8 +99,9 @@ impl Board {
         self.squares
             .iter()
             .map(|sq| match sq {
-                Square::Options(opts) => {
-                    opts.into_iter()
+                Square::Marks(marks) => {
+                    marks
+                        .into_iter()
                         .map(|a| a + 1)
                         .fold(String::new(), |mut a, b| {
                             a.push_str(&b.to_string());

src/square.rs

@@ -3,7 +3,7 @@ use bitmaps::Bitmap;
 #[derive(Clone, Debug)]
 pub enum Square {
     Value(u8),
-    Options(Bitmap<9>),
+    Marks(Bitmap<10>),
 }
 
 impl Square {
@@ -18,14 +18,18 @@ impl Square {
             '7' => Square::Value(7),
             '8' => Square::Value(8),
             '9' => Square::Value(9),
-            '.' => Square::Options(Bitmap::mask(9)),
+            '.' => {
+                let mut bm = Bitmap::mask(10);
+                bm.set(0, false);
+                Square::Marks(bm)
+            }
             _ => panic!("Unexpected character in input: {}", c),
         }
     }
 
     pub fn to_str(&self) -> String {
         match self {
-            Square::Options(_) => " ".to_string(),
+            Square::Marks(_) => " ".to_string(),
             Square::Value(v) => v.to_string(),
         }
     }

src/strategy/naked_single.rs

@@ -15,13 +15,13 @@ impl Strategy for NakedSingle {
             .iter()
             .enumerate()
             .filter_map(|(index, square)| match square {
-                Square::Options(marks) => Some((index, marks)),
+                Square::Marks(marks) => Some((index, marks)),
                 _ => None,
             })
             .find(|(_index, marks)| marks.len() == 1)
             .map(|(index, marks)| NakedSingle {
                 index,
-                value: marks.first_index().unwrap() as u8 + 1,
+                value: marks.first_index().unwrap() as u8,
             })
     }
 

src/validator.rs

@@ -53,7 +53,7 @@ pub fn validate_board(board: &Board) -> BoardState {
     }
 
     if board.squares.iter().any(|sq| match sq {
-        Square::Options(_) => true,
+        Square::Marks(_) => true,
         _ => false,
     }) {
         BoardState::InProgress