143 lines
3.7 KiB
Java
143 lines
3.7 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.constraintsolver.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 Seseman {
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static {
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System.loadLibrary("jniconstraintsolver");
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}
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/**
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*
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* Solves the Seseman convent problem.
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* See http://www.hakank.org/google_or_tools/seseman.py
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*
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*/
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private static void solve(int n) {
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Solver solver = new Solver("Seseman");
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//
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// data
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//
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final int border_sum = n * n;
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//
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// variables
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//
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IntVar[][] x = new IntVar[n][n];
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IntVar[] x_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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x[i][j] = solver.makeIntVar(0, n * n);
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x_flat[i * n + j] = x[i][j];
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}
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}
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IntVar total_sum = solver.makeSum(x_flat).var();
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//
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// constraints
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//
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// zero in all middle cells
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for(int i = 1; i < n-1; i++) {
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for(int j = 1; j < n-1; j++) {
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solver.addConstraint(solver.makeEquality(x[i][j], 0));
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}
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}
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// all borders must be >= 1
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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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if (i == 0 || j == 0 || i == n - 1 || j == n - 1) {
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solver.addConstraint(solver.makeGreaterOrEqual(x[i][j], 1));
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}
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}
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}
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// sum the four borders
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IntVar[] border1 = new IntVar[n];
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IntVar[] border2 = new IntVar[n];
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IntVar[] border3 = new IntVar[n];
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IntVar[] border4 = new IntVar[n];
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for(int i = 0; i < n; i++) {
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border1[i] = x[i][0];
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border2[i] = x[i][n - 1];
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border3[i] = x[0][i];
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border4[i] = x[n - 1][i];
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}
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solver.addConstraint(
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solver.makeSumEquality(border1, border_sum));
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solver.addConstraint(
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solver.makeSumEquality(border2, border_sum));
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solver.addConstraint(
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solver.makeSumEquality(border3, border_sum));
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solver.addConstraint(
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solver.makeSumEquality(border4, border_sum));
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//
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// search
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//
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DecisionBuilder db = solver.makePhase(x_flat,
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solver.INT_VAR_DEFAULT,
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solver.INT_VALUE_DEFAULT);
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solver.newSearch(db);
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while (solver.nextSolution()) {
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System.out.println("total_sum: " + total_sum.value());
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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(x[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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int n = 3;
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if (args.length > 0) {
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n = Integer.parseInt(args[0]);
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}
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Seseman.solve(n);
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}
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}
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