Add test: Hidato.

hidato_wikipedia: 4 guesses.

tests/hidato.rs

@@ -0,0 +1,111 @@
+//! Hidato.
+//!
+//! https://en.wikipedia.org/wiki/Hidato
+
+extern crate puzzle_solver;
+
+use puzzle_solver::{Puzzle,Solution,Val,VarToken};
+
+const WIDTH: usize = 8;
+const HEIGHT: usize = 8;
+const NA: i32 = -1;
+type Board = [[i32; WIDTH]; HEIGHT];
+
+fn make_hidato(board: &Board) -> (Puzzle, Vec<VarToken>) {
+    let mut sys = Puzzle::new();
+    let mut pos = Vec::new();
+    let mut count = 0;
+
+    for y in 0..HEIGHT {
+        for x in 0..WIDTH {
+            if board[y][x] != NA {
+                pos.push((WIDTH * y + x) as Val);
+                count = count + 1;
+            }
+        }
+    }
+
+    let vars = sys.new_vars_with_candidates_1d(count, &pos);
+
+    for y in 0..HEIGHT {
+        for x in 0..WIDTH {
+            if board[y][x] > 0 {
+                let idx = (board[y][x] - 1) as usize;
+                sys.set_value(vars[idx], (WIDTH * y + x) as Val);
+            }
+        }
+    }
+
+    sys.all_different(&vars);
+
+    let stride = WIDTH as Val;
+    let deltas = [
+        -stride - 1, -stride, -stride + 1,
+        -1, 1,
+        stride - 1, stride, stride + 1 ];
+
+    for i in 1..vars.len() {
+        let step = sys.new_var_with_candidates(&deltas);
+        sys.equals(vars[i], vars[i - 1] + step);
+    }
+
+    (sys, vars)
+}
+
+fn print_hidato(dict: &Solution, vars: &Vec<VarToken>) {
+    let mut board = [[NA; WIDTH]; HEIGHT];
+
+    for (idx, &var) in vars.iter().enumerate() {
+        let x = (dict[var] as usize) % WIDTH;
+        let y = (dict[var] as usize) / WIDTH;
+        board[y][x] = (idx as i32) + 1;
+    }
+
+    for y in 0..HEIGHT {
+        for x in 0..WIDTH {
+            if board[y][x] == NA {
+                print!(" --");
+            } else {
+                print!(" {:2}", board[y][x]);
+            }
+        }
+        println!();
+    }
+}
+
+fn verify_hidato(dict: &Solution, vars: &Vec<VarToken>, expected: &Board) {
+    for (idx, &var) in vars.iter().enumerate() {
+        let x = (dict[var] as usize) % WIDTH;
+        let y = (dict[var] as usize) / WIDTH;
+        assert_eq!((idx as i32) + 1, expected[y][x]);
+    }
+}
+
+#[test]
+fn hidato_wikipedia() {
+    let puzzle = [
+        [  0, 33, 35,  0,  0, NA, NA, NA ],
+        [  0,  0, 24, 22,  0, NA, NA, NA ],
+        [  0,  0,  0, 21,  0,  0, NA, NA ],
+        [  0, 26,  0, 13, 40, 11, NA, NA ],
+        [ 27,  0,  0,  0,  9,  0,  1, NA ],
+        [ NA, NA,  0,  0, 18,  0,  0, NA ],
+        [ NA, NA, NA, NA,  0,  7,  0,  0 ],
+        [ NA, NA, NA, NA, NA, NA,  5,  0 ] ];
+
+    let expected = [
+        [ 32, 33, 35, 36, 37, NA, NA, NA ],
+        [ 31, 34, 24, 22, 38, NA, NA, NA ],
+        [ 30, 25, 23, 21, 12, 39, NA, NA ],
+        [ 29, 26, 20, 13, 40, 11, NA, NA ],
+        [ 27, 28, 14, 19,  9, 10,  1, NA ],
+        [ NA, NA, 15, 16, 18,  8,  2, NA ],
+        [ NA, NA, NA, NA, 17,  7,  6,  3 ],
+        [ NA, NA, NA, NA, NA, NA,  5,  4 ] ];
+
+    let (mut sys, vars) = make_hidato(&puzzle);
+    let dict = sys.solve_any().expect("solution");
+    print_hidato(&dict, &vars);
+    verify_hidato(&dict, &vars, &expected);
+    println!("hidato_wikipedia: {} guesses", sys.num_guesses());
+}