Sudoku through the end of chapter 8

piston-tutorials/sudoku/src/gameboard.rs

@@ -8,17 +8,20 @@ const SIZE: usize = 9;
 pub struct Cell {
     pub value: u8,
     pub loaded: bool,
+    pub invalid: bool,
 }
 
 #[derive(Debug, PartialEq)]
 pub struct Gameboard {
     pub cells: [[Cell; SIZE]; SIZE],
+    pub completed: bool,
 }
 
 impl Gameboard {
     pub fn new() -> Gameboard {
         Gameboard {
             cells: [[Cell::default(); SIZE]; SIZE],
+            completed: false,
         }
     }
 
@@ -29,6 +32,7 @@ impl Gameboard {
                 ret.cells[i][j] = Cell {
                     value: col,
                     loaded: col != 0,
+                    invalid: false,
                 };
             }
         }
@@ -52,8 +56,15 @@ impl Gameboard {
 
     pub fn set(&mut self, ind: [usize; 2], val: u8) {
         if !self.cells[ind[1]][ind[0]].loaded {
+            self.validate(ind, val);
             self.cells[ind[1]][ind[0]].value = val;
         }
+
+        self.completed = self
+            .cells
+            .iter()
+            .flatten()
+            .all(|cell| !cell.invalid && cell.value != 0);
     }
 
     pub fn load_sdm(filename: &str) -> Self {
@@ -71,12 +82,53 @@ impl Gameboard {
                 cells[row][col] = Cell {
                     value,
                     loaded: value != 0,
+                    invalid: false,
                 };
                 col += 1;
             }
         }
 
-        Self { cells }
+        Self {
+            cells,
+            completed: false,
+        }
+    }
+
+    fn validate(&mut self, ind: [usize; 2], val: u8) {
+        let [b, a] = ind;
+        for i in 0..SIZE {
+            if i == a {
+                continue;
+            }
+            if self.cells[a][i].value == val {
+                self.cells[a][b].invalid = true;
+                return;
+            }
+        }
+
+        for i in 0..SIZE {
+            if i == b {
+                continue;
+            }
+            if self.cells[i][b].value == val {
+                self.cells[a][b].invalid = true;
+                return;
+            }
+        }
+
+        let (row, col) = (a / 3, b / 3);
+        for i in 3 * row..3 * row + 3 {
+            for j in 3 * col..3 * col + 3 {
+                if i == a && j == b {
+                    continue;
+                }
+                if self.cells[i][j].value == val {
+                    self.cells[a][b].invalid = true;
+                    return;
+                }
+            }
+        }
+        self.cells[a][b].invalid = false;
     }
 }