71 lines
2.2 KiB
C#
71 lines
2.2 KiB
C#
// Copyright 2010-2018 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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using System;
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using Google.OrTools.ConstraintSolver;
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/**
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* Shows how to write a custom decision builder.
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*/
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public class AssignFirstUnboundToMin : NetDecisionBuilder
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{
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public AssignFirstUnboundToMin(IntVar[] vars)
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{
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vars_ = vars;
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}
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public override Decision Next(Solver solver)
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{
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foreach (IntVar var in vars_)
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{
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if (!var.Bound())
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{
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return solver.MakeAssignVariableValue(var, var.Min());
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}
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}
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return null;
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}
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private IntVar[] vars_;
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}
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public class CsRabbitsPheasants
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{
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/**
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* Solves the rabbits + pheasants problem. We are seing 20 heads
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* and 56 legs. How many rabbits and how many pheasants are we thus
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* seeing?
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*/
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private static void Solve()
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{
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Solver solver = new Solver("RabbitsPheasants");
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IntVar rabbits = solver.MakeIntVar(0, 100, "rabbits");
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IntVar pheasants = solver.MakeIntVar(0, 100, "pheasants");
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solver.Add(rabbits + pheasants == 20);
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solver.Add(rabbits * 4 + pheasants * 2 == 56);
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DecisionBuilder db = new AssignFirstUnboundToMin(new IntVar[] { rabbits, pheasants });
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solver.NewSearch(db);
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solver.NextSolution();
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Console.WriteLine("Solved Rabbits + Pheasants in {0} ms, and {1} search tree branches.", solver.WallTime(),
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solver.Branches());
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Console.WriteLine(rabbits.ToString());
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Console.WriteLine(pheasants.ToString());
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solver.EndSearch();
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}
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public static void Main(String[] args)
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{
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Solve();
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}
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}
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