import java.io.*;
    import java.util.*;

    public class SudokuSolver {
        public static void main(String[] args) throws Exception {
            // Open the file containing the givens
            File file = new File(args[0]);
            FileReader rd = new FileReader(args[0]);

            // Process each grid in the file
            while (true) {
                Grid grid = Grid.create(rd);
                if (grid == null) {
                    // No more grids
                    break;
                }

                // Find a solution
                List<Grid> solutions = solve(grid);

                printSolutions(grid, solutions);
            }
        }

        // Recursive routine that
        private static List<Grid> solve(Grid grid) {
            List<Grid> solutions = new ArrayList<Grid>();
            solve(grid, solutions);
            return solutions;
        }

        private static void solve(Grid grid, List<Grid> solutions) {
            // Return if there is already more than two solution
            if (solutions.size() >= 2) {
                return;
            }

            // Find first empty cell
            int loc = grid.findEmptyCell();

            // If no empty cells are found, a solution is found
            if (loc < 0) {
                solutions.add(grid.clone());
                return;
            }

            // Try each of the 9 digits in this empty cell
            for (int n=1; n<10; n++) {
                if (grid.set(loc, n)) {
                    // With this cell set, work on the next cell
                    solve(grid, solutions);

                    // Clear the cell so that it can be filled with another digit
                    grid.clear(loc);
                }
            }
        }

        private static void printSolutions(Grid grid, List<Grid> solutions) {
            // Print the grid with the givens
            System.out.println("Original");
            System.out.println(grid);

            // Print the solution
            if (solutions.size() == 0) {
                System.out.println("Unsolveable");
            } else if (solutions.size() == 1) {
                System.out.println("Solved");
            } else {
                System.out.println("At least two solutions");
            }

            // Print the solution(s)
            for (int i=0; i<solutions.size(); i++) {
                System.out.println(solutions.get(i));
            }
            System.out.println();
            System.out.println();
        }
    }