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