117 lines
3.7 KiB
C#
117 lines
3.7 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 System.Collections;
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using System.IO;
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using System.Text.RegularExpressions;
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using Google.OrTools.ConstraintSolver;
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public class SetCoveringOPL
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{
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/**
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*
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* Solves a set covering problem.
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* See See http://www.hakank.org/or-tools/set_covering_opl.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("SetCoveringOPL");
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//
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// data
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//
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int num_workers = 32;
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int num_tasks = 15;
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// Which worker is qualified for each task.
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// Note: This is 1-based and will be made 0-base below.
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int[][] qualified = {
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new int[] { 1, 9, 19, 22, 25, 28, 31 }, new int[] { 2, 12, 15, 19, 21, 23, 27, 29, 30, 31, 32 },
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new int[] { 3, 10, 19, 24, 26, 30, 32 }, new int[] { 4, 21, 25, 28, 32 },
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new int[] { 5, 11, 16, 22, 23, 27, 31 }, new int[] { 6, 20, 24, 26, 30, 32 },
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new int[] { 7, 12, 17, 25, 30, 31 }, new int[] { 8, 17, 20, 22, 23 },
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new int[] { 9, 13, 14, 26, 29, 30, 31 }, new int[] { 10, 21, 25, 31, 32 },
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new int[] { 14, 15, 18, 23, 24, 27, 30, 32 }, new int[] { 18, 19, 22, 24, 26, 29, 31 },
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new int[] { 11, 20, 25, 28, 30, 32 }, new int[] { 16, 19, 23, 31 },
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new int[] { 9, 18, 26, 28, 31, 32 }
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};
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int[] cost = { 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 8, 9 };
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//
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// Decision variables
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//
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IntVar[] hire = solver.MakeIntVarArray(num_workers, 0, 1, "workers");
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IntVar total_cost = hire.ScalProd(cost).Var();
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//
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// Constraints
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//
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for (int j = 0; j < num_tasks; j++)
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{
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// Sum the cost for hiring the qualified workers
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// (also, make 0-base).
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int len = qualified[j].Length;
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IntVar[] tmp = new IntVar[len];
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for (int c = 0; c < len; c++)
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{
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tmp[c] = hire[qualified[j][c] - 1];
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}
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solver.Add(tmp.Sum() >= 1);
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}
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//
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// objective
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//
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OptimizeVar objective = total_cost.Minimize(1);
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//
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// Search
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//
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DecisionBuilder db = solver.MakePhase(hire, Solver.CHOOSE_FIRST_UNBOUND, Solver.ASSIGN_MIN_VALUE);
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solver.NewSearch(db, objective);
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while (solver.NextSolution())
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{
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Console.WriteLine("Cost: " + total_cost.Value());
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Console.Write("Hire: ");
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for (int i = 0; i < num_workers; i++)
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{
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if (hire[i].Value() == 1)
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{
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Console.Write(i + " ");
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}
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}
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Console.WriteLine("\n");
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}
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Console.WriteLine("\nSolutions: {0}", solver.Solutions());
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Console.WriteLine("WallTime: {0}ms", solver.WallTime());
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Console.WriteLine("Failures: {0}", solver.Failures());
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Console.WriteLine("Branches: {0} ", 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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