136 lines
3.4 KiB
Rust
136 lines
3.4 KiB
Rust
//! Sudoku.
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//!
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//! https://en.wikipedia.org/wiki/Sudoku
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extern crate puzzle_solver;
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use puzzle_solver::{Puzzle,Solution,Val,VarToken};
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const SQRT_SIZE: usize = 3;
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const SIZE: usize = 9;
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type Board = [[Val; SIZE]; SIZE];
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fn make_sudoku(board: &Board) -> (Puzzle, Vec<Vec<VarToken>>) {
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let mut sys = Puzzle::new();
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let vars = sys.new_vars_with_candidates_2d(SIZE, SIZE, &[1,2,3,4,5,6,7,8,9]);
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for y in 0..SIZE {
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sys.all_different(&vars[y]);
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}
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for x in 0..SIZE {
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sys.all_different(vars.iter().map(|row| &row[x]));
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}
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for block in 0..SIZE {
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let x0 = SQRT_SIZE * (block % SQRT_SIZE);
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let y0 = SQRT_SIZE * (block / SQRT_SIZE);
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sys.all_different((0..SIZE).map(|n|
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&vars[y0 + (n / SQRT_SIZE)][x0 + (n % SQRT_SIZE)]));
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}
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for y in 0..SIZE {
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for x in 0..SIZE {
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let value = board[y][x];
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if value != 0 {
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sys.set_value(vars[y][x], value);
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}
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}
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}
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(sys, vars)
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}
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fn print_sudoku(dict: &Solution, vars: &Vec<Vec<VarToken>>) {
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for y in 0..SIZE {
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if y % SQRT_SIZE == 0 {
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println!();
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}
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for x in 0..SIZE {
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print!("{}{}",
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if x % SQRT_SIZE == 0 { " " } else { "" },
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dict[vars[y][x]]);
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}
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println!();
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}
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}
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fn verify_sudoku(dict: &Solution, vars: &Vec<Vec<VarToken>>, expected: &Board) {
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for y in 0..SIZE {
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for x in 0..SIZE {
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assert_eq!(dict[vars[y][x]], expected[y][x]);
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}
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}
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}
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#[test]
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fn sudoku_hardest() {
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let puzzle = [
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[ 8,0,0, 0,0,0, 0,0,0 ],
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[ 0,0,3, 6,0,0, 0,0,0 ],
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[ 0,7,0, 0,9,0, 2,0,0 ],
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[ 0,5,0, 0,0,7, 0,0,0 ],
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[ 0,0,0, 0,4,5, 7,0,0 ],
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[ 0,0,0, 1,0,0, 0,3,0 ],
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[ 0,0,1, 0,0,0, 0,6,8 ],
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[ 0,0,8, 5,0,0, 0,1,0 ],
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[ 0,9,0, 0,0,0, 4,0,0 ] ];
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let expected = [
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[ 8,1,2, 7,5,3, 6,4,9 ],
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[ 9,4,3, 6,8,2, 1,7,5 ],
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[ 6,7,5, 4,9,1, 2,8,3 ],
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[ 1,5,4, 2,3,7, 8,9,6 ],
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[ 3,6,9, 8,4,5, 7,2,1 ],
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[ 2,8,7, 1,6,9, 5,3,4 ],
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[ 5,2,1, 9,7,4, 3,6,8 ],
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[ 4,3,8, 5,2,6, 9,1,7 ],
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[ 7,9,6, 3,1,8, 4,5,2 ] ];
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let (mut sys, vars) = make_sudoku(&puzzle);
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let solution = sys.solve_any().expect("solution");
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print_sudoku(&solution, &vars);
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verify_sudoku(&solution, &vars, &expected);
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println!("sudoku_hardest: {} guesses", sys.num_guesses());
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}
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#[test]
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fn sudoku_wikipedia() {
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let puzzle = [
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[ 5,3,0, 0,7,0, 0,0,0 ],
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[ 6,0,0, 1,9,5, 0,0,0 ],
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[ 0,9,8, 0,0,0, 0,6,0 ],
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[ 8,0,0, 0,6,0, 0,0,3 ],
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[ 4,0,0, 8,0,3, 0,0,1 ],
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[ 7,0,0, 0,2,0, 0,0,6 ],
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[ 0,6,0, 0,0,0, 2,8,0 ],
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[ 0,0,0, 4,1,9, 0,0,5 ],
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[ 0,0,0, 0,8,0, 0,7,9 ] ];
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let expected = [
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[ 5,3,4, 6,7,8, 9,1,2 ],
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[ 6,7,2, 1,9,5, 3,4,8 ],
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[ 1,9,8, 3,4,2, 5,6,7 ],
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[ 8,5,9, 7,6,1, 4,2,3 ],
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[ 4,2,6, 8,5,3, 7,9,1 ],
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[ 7,1,3, 9,2,4, 8,5,6 ],
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[ 9,6,1, 5,3,7, 2,8,4 ],
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[ 2,8,7, 4,1,9, 6,3,5 ],
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[ 3,4,5, 2,8,6, 1,7,9 ] ];
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let (mut sys, vars) = make_sudoku(&puzzle);
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let solution = sys.solve_any().expect("solution");
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print_sudoku(&solution, &vars);
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verify_sudoku(&solution, &vars, &expected);
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println!("sudoku_wikipedia: {} guesses", sys.num_guesses());
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}
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