diff --git a/puzzles/challenge2.csv b/puzzles/challenge2.csv new file mode 100644 index 0000000..0dc08d9 --- /dev/null +++ b/puzzles/challenge2.csv @@ -0,0 +1,10 @@ +4,0,0,0,2,3,0,0,0 +0,2,0,0,4,0,5,8,0 +0,1,0,0,0,6,0,0,0 +0,0,6,0,5,0,2,0,0 +2,3,0,6,0,4,8,0,0 +0,4,0,0,0,0,0,3,0 +1,6,0,2,3,0,0,0,0 +0,0,5,7,0,1,0,0,0 +0,0,0,0,6,5,0,0,0 + diff --git a/src/main.rs b/src/main.rs index b7e7442..127bd66 100644 --- a/src/main.rs +++ b/src/main.rs @@ -337,6 +337,38 @@ impl Grid { } } +impl Clone for Grid { + fn clone(&self) -> Self { + let mut new = Grid::new(); + new.clone_from(&self); + + return new; + } + + fn clone_from(&mut self, source: &Self) { + for x in 0..9 { + for y in 0..9 { + let source_value = source.get(x, y).unwrap().get_value_copy(); + self.get(x, y).unwrap().set_value_exact(source_value); + } + } + + for i in 0..9 { + let new_row = &*self.rows.get(i).unwrap().borrow(); + let source_row = &*source.rows.get(i).unwrap().borrow(); + new_row.do_update.replace(source_row.do_update()); + + let new_column = &*self.columns.get(i).unwrap().borrow(); + let source_column = &*source.columns.get(i).unwrap().borrow(); + new_column.do_update.replace(source_column.do_update()); + + let new_section = &*self.sections.get(i).unwrap().borrow(); + let source_section = &*source.sections.get(i).unwrap().borrow(); + new_section.do_update.replace(source_section.do_update()); + } + } +} + @@ -346,7 +378,6 @@ impl Grid { struct FauxCell{ index: usize, - real_cell: Rc, possibilities: HashSet, in_group: bool } @@ -364,12 +395,9 @@ impl FauxCell { struct FauxLine (Vec); impl FauxLine { - fn get_mut(&mut self, index: usize) -> Option<&mut FauxCell>{ - return self.0.get_mut(index); - } fn num_in_group(&self) -> usize { - self.0.iter().filter(|fauxcell| fauxcell.in_group).count() + self.0.iter().filter(|faux_cell| faux_cell.in_group).count() } fn num_out_group(&self) -> usize { @@ -432,7 +460,6 @@ fn bisect_possibility_groups(line: &Line, cells_of_interest: Vec){ let faux_cell = FauxCell { index: i, - real_cell: cell, possibilities: faux_possibilities, in_group: false }; @@ -754,8 +781,70 @@ fn solve_line(grid: &Grid, line: &Line){ } -fn solve_grid(grid: &Grid) { - 'outer: loop { +fn find_smallest_cell(grid: &Grid) -> Option>{ + // Find a cell of smallest size (in terms of possibilities) and make a guess + // Can assume that no cells of only possibility 1 exist + + let mut smallest_cell : Option> = None; + let mut smallest_size = usize::MAX; + + 'outer: for x in 0..9 { + for y in 0..9 { + let cell_rc = grid.get(x, y).unwrap(); + let cell = &*grid.get(x, y).unwrap(); + let cell_value = &*cell.value.borrow(); + + match cell_value { + CellValue::UNKNOWN(possibilities) => { + if (possibilities.len() < smallest_size) && (possibilities.len() > 0){ + smallest_size = possibilities.len(); + smallest_cell = Some(cell_rc); + } + }, + _ => {} + } + + if smallest_size <= 2 { + break 'outer; // We aren't going to get smaller + } + + } + } + smallest_cell + +} + + +enum SolveStatus { + COMPLETE, + UNFINISHED, + INVALID +} + +fn solve_grid(grid: &mut Grid) -> SolveStatus{ + // Code is kind of messy so here it goes - solve_grid first tries to solve without any guesses + // If that's not enough and a guess is required, then solve_grid_guess is called + // solve_grid_guess runs through all the possibilities for the smallest cell, trying to solve them + // through calling this function. + // solve_grid_no_guess tries to solve without any guesses. + + let mut status = solve_grid_no_guess(grid); + status = match status { + SolveStatus::UNFINISHED => { + solve_grid_guess(grid) + }, + _ => {status} + }; + + match status { + SolveStatus::UNFINISHED => panic!("solve_grid_guess should never return UNFINISHED"), + _ => return status + } +} + +fn solve_grid_no_guess(grid: &mut Grid) -> SolveStatus{ + + loop { let mut ran_something = false; for (_index, line_ref) in grid.rows.iter().enumerate() { //println!("Processing row {}", _index); @@ -783,8 +872,7 @@ fn solve_grid(grid: &Grid) { } if !ran_something{ // No lines have changed since we last analyzed them - println!("Unable to find a solution (no changes)"); - break 'outer; + return SolveStatus::UNFINISHED; } // Check if complete or invalid @@ -799,8 +887,8 @@ fn solve_grid(grid: &Grid) { CellValue::UNKNOWN(possibilities) => { appears_complete = false; if possibilities.len() == 0 { - println!("Unable to find a solution"); - break 'outer; + return SolveStatus::INVALID; + } }, CellValue::FIXED(_) => {} @@ -809,70 +897,52 @@ fn solve_grid(grid: &Grid) { } if appears_complete { - break 'outer; + return SolveStatus::COMPLETE; } - } + } -/* -fn main() { - let grid = Grid::new(); +fn solve_grid_guess(grid: &mut Grid) -> SolveStatus{ + let smallest_cell = find_smallest_cell(grid); + let smallest_cell = match smallest_cell { + Some(cell) => cell, + None => return SolveStatus::INVALID + }; - println!("Now setting some values"); + let possibilities = smallest_cell.get_value_possibilities().unwrap(); + for (_index, &digit) in possibilities.iter().enumerate() { + let mut grid_copy = grid.clone(); + grid_copy.get(smallest_cell.x, smallest_cell.y).unwrap().set(digit); + let status = solve_grid(&mut grid_copy); - - grid.get(0, 4).unwrap().set(8); - grid.get(0, 5).unwrap().set(5); - grid.get(0, 6).unwrap().set(6); + match status { + SolveStatus::COMPLETE => { + grid.clone_from(&grid_copy); + return SolveStatus::COMPLETE; + }, + SolveStatus::UNFINISHED => { + panic!("solve_grid should never return UNFINISHED") + }, + SolveStatus::INVALID => { + continue; + } + } + } - grid.get(2, 3).unwrap().set(9); - grid.get(2, 4).unwrap().set(4); - grid.get(2, 5).unwrap().set(3); - grid.get(2, 6).unwrap().set(5); - grid.get(2, 7).unwrap().set(7); + return SolveStatus::INVALID; - grid.get(3, 0).unwrap().set(8); - grid.get(3, 2).unwrap().set(2); - grid.get(3, 3).unwrap().set(6); - grid.get(3, 4).unwrap().set(7); - grid.get(3, 5).unwrap().set(4); - grid.get(3, 6).unwrap().set(9); - - grid.get(4, 4).unwrap().set(9); - grid.get(4, 8).unwrap().set(5); - - grid.get(5, 1).unwrap().set(6); - grid.get(5, 6).unwrap().set(2); - - grid.get(6, 1).unwrap().set(8); - grid.get(6, 8).unwrap().set(2); - - grid.get(7, 3).unwrap().set(7); - grid.get(7, 5).unwrap().set(6); - grid.get(7, 7).unwrap().set(5); - grid.get(7, 8).unwrap().set(4); - - grid.get(8, 2).unwrap().set(7); - grid.get(8, 3).unwrap().set(4); - - grid.print(); - - println!("Now going to start a solver on it"); - - solve_grid(&grid); - grid.print(); - println!("\n"); } -*/ + + fn main() { - let grid = read_grid().unwrap(); + let mut grid = read_grid().unwrap(); grid.print(); println!("Solving grid"); - solve_grid(&grid); + solve_grid(&mut grid); grid.print(); }