108 lines
3.0 KiB
Java
108 lines
3.0 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.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.*;
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public class LeastDiff {
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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 Least Diff problem.
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* See http://www.hakank.org/google_or_tools/least_diff.py
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*
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*/
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private static void solve() {
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final int base = 10;
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Solver solver = new Solver("LeastDiff");
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//
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// Variables
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//
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IntVar a = solver.makeIntVar(0, base - 1, "a");
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IntVar b = solver.makeIntVar(0, base - 1, "b");
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IntVar c = solver.makeIntVar(0, base - 1, "c");
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IntVar d = solver.makeIntVar(0, base - 1, "d");
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IntVar e = solver.makeIntVar(0, base - 1, "e");
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IntVar f = solver.makeIntVar(0, base - 1, "f");
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IntVar g = solver.makeIntVar(0, base - 1, "g");
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IntVar h = solver.makeIntVar(0, base - 1, "h");
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IntVar i = solver.makeIntVar(0, base - 1, "i");
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IntVar j = solver.makeIntVar(0, base - 1, "j");
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IntVar[] all = {a,b,c,d,e,f,g,h,i,j};
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//
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// Constraints
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//
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int[] coeffs = {10000, 1000, 100, 10, 1};
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IntVar x = solver.makeScalProd(new IntVar[]{a,b,c,d,e}, coeffs).var();
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x.setName("x");
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IntVar y = solver.makeScalProd(new IntVar[]{f,g,h,i,j}, coeffs).var();
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y.setName("y");
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// a > 0
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solver.addConstraint(solver.makeGreater(a, 0));
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// f > 0
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solver.addConstraint(solver.makeGreater(f, 0));
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// diff = x - y
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IntVar diff = solver.makeDifference(x, y).var();
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diff.setName("diff");
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solver.addConstraint(solver.makeAllDifferent(all));
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//
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// Objective
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//
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OptimizeVar obj = solver.makeMinimize(diff, 1);
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//
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// Search
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//
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DecisionBuilder db = solver.makePhase(all,
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solver.CHOOSE_PATH,
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solver.ASSIGN_MIN_VALUE);
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solver.newSearch(db, obj);
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while (solver.nextSolution()) {
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System.out.println("" + x.value() + " - " +
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y.value() + " = " + diff.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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LeastDiff.solve();
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}
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}
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