137 lines
3.6 KiB
C#
137 lines
3.6 KiB
C#
//
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// Copyright 2012 Hakan Kjellerstrand
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//
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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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public class MrSmith
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{
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/**
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*
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* Mr Smith problem.
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*
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* From an IF Prolog example (http://www.ifcomputer.de/)
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* """
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* The Smith family and their three children want to pay a visit but they
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* do not all have the time to do so. Following are few hints who will go
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* and who will not:
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* o If Mr Smith comes, his wife will come too.
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* o At least one of their two sons Matt and John will come.
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* o Either Mrs Smith or Tim will come, but not both.
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* o Either Tim and John will come, or neither will come.
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* o If Matt comes, then John and his father will
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* also come.
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* """
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*
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* The answer should be:
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* Mr_Smith_comes = 0
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* Mrs_Smith_comes = 0
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* Matt_comes = 0
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* John_comes = 1
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* Tim_comes = 1
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*
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*
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* Also see http://www.hakank.org/or-tools/mr_smith.py
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*
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*/
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private static void Solve()
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{
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Solver solver = new Solver("MrSmith");
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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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// Decision variables
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//
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IntVar[] x = solver.MakeIntVarArray(n, 0, 1, "x");
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IntVar Mr_Smith = x[0];
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IntVar Mrs_Smith = x[1];
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IntVar Matt = x[2];
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IntVar John = x[3];
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IntVar Tim = x[4];
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//
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// Constraints
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//
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//
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// I've kept the MiniZinc constraints for clarity
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// and debugging.
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//
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// If Mr Smith comes then his wife will come too.
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// (Mr_Smith -> Mrs_Smith)
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solver.Add(Mr_Smith - Mrs_Smith <= 0);
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// At least one of their two sons Matt and John will come.
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// (Matt \/ John)
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solver.Add(Matt+John >= 1);
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// Either Mrs Smith or Tim will come but not both.
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// bool2int(Mrs_Smith) + bool2int(Tim) = 1
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// (Mrs_Smith xor Tim)
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solver.Add(Mrs_Smith + Tim == 1);
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// Either Tim and John will come or neither will come.
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// (Tim = John)
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solver.Add(Tim == John);
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// If Matt comes /\ then John and his father will also come.
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// (Matt -> (John /\ Mr_Smith))
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solver.Add(Matt - (John*Mr_Smith) <= 0);
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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.CHOOSE_MIN_SIZE_LOWEST_MIN,
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Solver.ASSIGN_CENTER_VALUE);
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solver.NewSearch(db);
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while (solver.NextSolution()) {
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for(int i = 0; i < n; i++) {
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Console.Write(x[i].Value() + " ");
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}
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Console.WriteLine("\n");
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Console.WriteLine("Mr Smith : {0}", Mr_Smith.Value());
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Console.WriteLine("Mrs Smith: {0}", Mrs_Smith.Value());
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Console.WriteLine("Matt : {0}", Matt.Value());
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Console.WriteLine("John : {0}", John.Value());
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Console.WriteLine("Tim : {0}", Tim.Value());
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}
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Console.WriteLine("\nSolutions: " + solver.Solutions());
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Console.WriteLine("WallTime: " + solver.WallTime() + "ms ");
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Console.WriteLine("Failures: " + solver.Failures());
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Console.WriteLine("Branches: " + solver.Branches());
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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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