122 lines
3.2 KiB
Java
122 lines
3.2 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 AllDifferentExcept0 {
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static {
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System.loadLibrary("jniortools");
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}
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//
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// alldifferent_except_0(solver, x)
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//
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// A decomposition of the global constraint
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// alldifferent_except_0, i.e. all values
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// must be either distinct, or 0.
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//
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public static void alldifferent_except_0(Solver solver, IntVar[] a) {
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int n = a.length;
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for(int i = 0; i < n; i++) {
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for(int j = 0; j < i; j++) {
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IntVar bi = solver.makeIsDifferentCstVar(a[i], 0);
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IntVar bj = solver.makeIsDifferentCstVar(a[j], 0);
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IntVar bij = solver.makeIsDifferentCstVar(a[i], a[j]);
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solver.addConstraint(
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solver.makeLessOrEqual(
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solver.makeProd(bi, bj).var(), bij));
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}
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}
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}
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/**
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*
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* Implements a (decomposition) of global constraint
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* alldifferent_except_0.
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* See http://www.hakank.org/google_or_tools/circuit.py
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*
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*/
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private static void solve() {
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Solver solver = new Solver("AllDifferentExcept0");
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//
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// data
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//
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int n = 5;
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//
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// variables
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//
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IntVar[] x = solver.makeIntVarArray(n, 0, n - 1, "x");
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//
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// constraints
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//
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alldifferent_except_0(solver, x);
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// we also require at least 2 0's
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IntVar[] z_tmp = solver.makeBoolVarArray(n, "z_tmp");
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for(int i = 0; i < n; i++) {
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solver.addConstraint(
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solver.makeIsEqualCstCt(x[i], 0, z_tmp[i]));
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}
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IntVar z = solver.makeSum(z_tmp).var();
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solver.addConstraint(solver.makeEquality(z, 2));
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//
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// search
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//
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DecisionBuilder db = solver.makePhase(x,
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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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//
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// output
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//
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while (solver.nextSolution()) {
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System.out.print("x: ");
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for(int i = 0; i < n; i++) {
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System.out.print(x[i].value() + " ");
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}
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System.out.println(" z: " + z.value());
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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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AllDifferentExcept0.solve();
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}
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}
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