137 lines
3.9 KiB
Java
137 lines
3.9 KiB
Java
// Copyright 2011 Hakan Kjellerstrand hakank@gmail.com
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
import java.io.*;
|
|
import java.util.*;
|
|
import java.text.*;
|
|
|
|
import com.google.ortools.constraintsolver.DecisionBuilder;
|
|
import com.google.ortools.constraintsolver.IntVar;
|
|
import com.google.ortools.constraintsolver.Solver;
|
|
|
|
public class Sudoku {
|
|
|
|
static {
|
|
System.loadLibrary("jniortools");
|
|
}
|
|
|
|
|
|
/**
|
|
*
|
|
* Solves a Sudoku problem.
|
|
*
|
|
*/
|
|
private static void solve() {
|
|
|
|
Solver solver = new Solver("Sudoku");
|
|
|
|
int cell_size = 3;
|
|
int n = cell_size * cell_size;
|
|
|
|
// 0 marks an unknown value
|
|
int[][] initial_grid = new int[][] {{0, 6, 0, 0, 5, 0, 0, 2, 0},
|
|
{0, 0, 0, 3, 0, 0, 0, 9, 0},
|
|
{7, 0, 0, 6, 0, 0, 0, 1, 0},
|
|
{0, 0, 6, 0, 3, 0, 4, 0, 0},
|
|
{0, 0, 4, 0, 7, 0, 1, 0, 0},
|
|
{0, 0, 5, 0, 9, 0, 8, 0, 0},
|
|
{0, 4, 0, 0, 0, 1, 0, 0, 6},
|
|
{0, 3, 0, 0, 0, 8, 0, 0, 0},
|
|
{0, 2, 0, 0, 4, 0, 0, 5, 0}};
|
|
|
|
//
|
|
// variables
|
|
//
|
|
IntVar[][] grid = new IntVar[n][n];
|
|
IntVar[] grid_flat = new IntVar[n * n];
|
|
|
|
for(int i = 0; i < n; i++) {
|
|
for(int j = 0; j < n; j++) {
|
|
grid[i][j] = solver.makeIntVar(1, 9, "grid[" + i +"," + j + "]");
|
|
grid_flat[i * n + j] = grid[i][j];
|
|
}
|
|
}
|
|
|
|
//
|
|
// constraints
|
|
//
|
|
|
|
// init and rows
|
|
for(int i = 0; i < n; i++) {
|
|
IntVar[] row = new IntVar[n];
|
|
for(int j = 0; j < n; j++) {
|
|
if (initial_grid[i][j] > 0) {
|
|
solver.addConstraint(
|
|
solver.makeEquality(grid[i][j], initial_grid[i][j]));
|
|
}
|
|
row[j] = grid[i][j];
|
|
}
|
|
solver.addConstraint(solver.makeAllDifferent(row));
|
|
}
|
|
|
|
// columns
|
|
for(int j = 0; j < n; j++) {
|
|
IntVar[] col = new IntVar[n];
|
|
for(int i = 0; i < n; i++) {
|
|
col[i] = grid[i][j];
|
|
}
|
|
solver.addConstraint(solver.makeAllDifferent(col));
|
|
}
|
|
|
|
// cells
|
|
for(int i = 0; i < cell_size; i++) {
|
|
for(int j = 0; j < cell_size; j++) {
|
|
IntVar[] cell = new IntVar[n];
|
|
for(int di = 0; di < cell_size; di++) {
|
|
for(int dj = 0; dj < cell_size; dj++) {
|
|
cell[di * cell_size + dj] =
|
|
grid[i * cell_size + di][j * cell_size + dj];
|
|
}
|
|
}
|
|
solver.addConstraint(solver.makeAllDifferent(cell));
|
|
}
|
|
}
|
|
|
|
//
|
|
// Search
|
|
//
|
|
DecisionBuilder db = solver.makePhase(grid_flat,
|
|
solver.INT_VAR_SIMPLE,
|
|
solver.INT_VALUE_SIMPLE);
|
|
|
|
solver.newSearch(db);
|
|
|
|
while (solver.nextSolution()) {
|
|
for(int i = 0; i < n; i++) {
|
|
for(int j = 0; j < n; j++) {
|
|
System.out.print(grid[i][j].value() + " ");
|
|
}
|
|
System.out.println();
|
|
}
|
|
System.out.println();
|
|
}
|
|
solver.endSearch();
|
|
|
|
// Statistics
|
|
System.out.println();
|
|
System.out.println("Solutions: " + solver.solutions());
|
|
System.out.println("Failures: " + solver.failures());
|
|
System.out.println("Branches: " + solver.branches());
|
|
System.out.println("Wall time: " + solver.wallTime() + "ms");
|
|
|
|
}
|
|
|
|
public static void main(String[] args) throws Exception {
|
|
Sudoku.solve();
|
|
}
|
|
}
|