Data commit

Task/Sudoku/Rust/sudoku.rust

@@ -0,0 +1,64 @@
+type Sudoku = [u8; 81];
+
+fn is_valid(val: u8, x: usize, y: usize, sudoku_ar: &mut Sudoku) -> bool {
+    (0..9).all(|i| sudoku_ar[y * 9 + i] != val && sudoku_ar[i * 9 + x] != val) && {
+        let (start_x, start_y) = ((x / 3) * 3, (y / 3) * 3);
+        (start_y..start_y + 3).all(|i| (start_x..start_x + 3).all(|j| sudoku_ar[i * 9 + j] != val))
+    }
+}
+
+fn place_number(pos: usize, sudoku_ar: &mut Sudoku) -> bool {
+    (pos..81).find(|&p| sudoku_ar[p] == 0).map_or(true, |pos| {
+        let (x, y) = (pos % 9, pos / 9);
+        for n in 1..10 {
+            if is_valid(n, x, y, sudoku_ar) {
+                sudoku_ar[pos] = n;
+                if place_number(pos + 1, sudoku_ar) {
+                    return true;
+                }
+                sudoku_ar[pos] = 0;
+            }
+        }
+        false
+    })
+}
+
+fn pretty_print(sudoku_ar: Sudoku) {
+    let line_sep = "------+-------+------";
+    println!("{}", line_sep);
+    for (i, e) in sudoku_ar.iter().enumerate() {
+        print!("{} ", e);
+        if (i + 1) % 3 == 0 && (i + 1) % 9 != 0 {
+            print!("| ");
+        }
+        if (i + 1) % 9 == 0 {
+            println!(" ");
+        }
+        if (i + 1) % 27 == 0 {
+            println!("{}", line_sep);
+        }
+    }
+}
+
+fn solve(sudoku_ar: &mut Sudoku) -> bool {
+    place_number(0, sudoku_ar)
+}
+
+fn main() {
+    let mut sudoku_ar: Sudoku = [
+        8, 5, 0, 0, 0, 2, 4, 0, 0,
+        7, 2, 0, 0, 0, 0, 0, 0, 9,
+        0, 0, 4, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 1, 0, 7, 0, 0, 2,
+        3, 0, 5, 0, 0, 0, 9, 0, 0,
+        0, 4, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 8, 0, 0, 7, 0,
+        0, 1, 7, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 3, 6, 0, 4, 0
+    ];
+    if solve(&mut sudoku_ar) {
+        pretty_print(sudoku_ar);
+    } else {
+        println!("Unsolvable");
+    }
+}