94 lines
2.7 KiB
Java
94 lines
2.7 KiB
Java
// Copyright 2011 Hakan Kjellerstrand hakank@gmail.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.contrib;
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import com.google.ortools.Loader;
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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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import java.io.*;
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import java.text.*;
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import java.util.*;
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public class AllInterval {
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/**
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* Implements the all interval problem. See http://www.hakank.org/google_or_tools/all_interval.py
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*/
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private static void solve(int n) {
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Solver solver = new Solver("AllInterval");
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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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IntVar[] diffs = solver.makeIntVarArray(n - 1, 1, n - 1, "diffs");
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//
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// constraints
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//
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solver.addConstraint(solver.makeAllDifferent(x));
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solver.addConstraint(solver.makeAllDifferent(diffs));
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for (int k = 0; k < n - 1; k++) {
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solver.addConstraint(solver.makeEquality(
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diffs[k], solver.makeAbs(solver.makeDifference(x[k + 1], x[k])).var()));
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}
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// symmetry breaking
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solver.addConstraint(solver.makeLess(x[0], x[n - 1]));
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solver.addConstraint(solver.makeLess(diffs[0], diffs[1]));
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//
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// search
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//
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DecisionBuilder db = solver.makePhase(x, solver.CHOOSE_FIRST_UNBOUND, solver.ASSIGN_MIN_VALUE);
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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.print("\ndiffs: ");
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for (int i = 0; i < n - 1; i++) {
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System.out.print(diffs[i].value() + " ");
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}
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System.out.println("\n");
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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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Loader.loadNativeLibraries();
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int n = 12;
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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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AllInterval.solve(n);
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}
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}
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