78 lines
2.7 KiB
Java
78 lines
2.7 KiB
Java
// Copyright 2010-2021 Google LLC
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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.sat.samples;
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import com.google.ortools.Loader;
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import com.google.ortools.sat.CpModel;
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import com.google.ortools.sat.CpSolver;
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import com.google.ortools.sat.CpSolverSolutionCallback;
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import com.google.ortools.sat.IntVar;
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/** Code sample that solves a model and displays a small number of solutions. */
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public class StopAfterNSolutionsSampleSat {
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static class VarArraySolutionPrinterWithLimit extends CpSolverSolutionCallback {
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public VarArraySolutionPrinterWithLimit(IntVar[] variables, int limit) {
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variableArray = variables;
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solutionLimit = limit;
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}
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@Override
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public void onSolutionCallback() {
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System.out.printf("Solution #%d: time = %.02f s%n", solutionCount, wallTime());
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for (IntVar v : variableArray) {
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System.out.printf(" %s = %d%n", v.getName(), value(v));
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}
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solutionCount++;
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if (solutionCount >= solutionLimit) {
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System.out.printf("Stop search after %d solutions%n", solutionLimit);
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stopSearch();
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}
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}
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public int getSolutionCount() {
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return solutionCount;
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}
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private int solutionCount;
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private final IntVar[] variableArray;
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private final int solutionLimit;
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}
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public static void main(String[] args) throws Exception {
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Loader.loadNativeLibraries();
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// Create the model.
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CpModel model = new CpModel();
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// Create the variables.
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int numVals = 3;
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IntVar x = model.newIntVar(0, numVals - 1, "x");
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IntVar y = model.newIntVar(0, numVals - 1, "y");
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IntVar z = model.newIntVar(0, numVals - 1, "z");
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// Create a solver and solve the model.
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CpSolver solver = new CpSolver();
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VarArraySolutionPrinterWithLimit cb =
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new VarArraySolutionPrinterWithLimit(new IntVar[] {x, y, z}, 5);
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// Tell the solver to enumerate all solutions.
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solver.getParameters().setEnumerateAllSolutions(true);
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// And solve.
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solver.solve(model, cb);
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System.out.println(cb.getSolutionCount() + " solutions found.");
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if (cb.getSolutionCount() != 5) {
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throw new RuntimeException("Did not stop the search correctly.");
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}
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}
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}
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