125 lines
5.2 KiB
C#
125 lines
5.2 KiB
C#
// Copyright 2010-2025 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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// [START program]
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// [START import]
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using System;
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using System.Collections.Generic;
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using Google.OrTools.ConstraintSolver;
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// [END import]
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/// <summary>
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/// Minimal TSP using distance matrix.
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/// </summary>
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public class TspCities
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{
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// [START data_model]
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class DataModel
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{
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public long[,] DistanceMatrix = {
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{ 0, 2451, 713, 1018, 1631, 1374, 2408, 213, 2571, 875, 1420, 2145, 1972 },
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{ 2451, 0, 1745, 1524, 831, 1240, 959, 2596, 403, 1589, 1374, 357, 579 },
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{ 713, 1745, 0, 355, 920, 803, 1737, 851, 1858, 262, 940, 1453, 1260 },
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{ 1018, 1524, 355, 0, 700, 862, 1395, 1123, 1584, 466, 1056, 1280, 987 },
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{ 1631, 831, 920, 700, 0, 663, 1021, 1769, 949, 796, 879, 586, 371 },
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{ 1374, 1240, 803, 862, 663, 0, 1681, 1551, 1765, 547, 225, 887, 999 },
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{ 2408, 959, 1737, 1395, 1021, 1681, 0, 2493, 678, 1724, 1891, 1114, 701 },
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{ 213, 2596, 851, 1123, 1769, 1551, 2493, 0, 2699, 1038, 1605, 2300, 2099 },
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{ 2571, 403, 1858, 1584, 949, 1765, 678, 2699, 0, 1744, 1645, 653, 600 },
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{ 875, 1589, 262, 466, 796, 547, 1724, 1038, 1744, 0, 679, 1272, 1162 },
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{ 1420, 1374, 940, 1056, 879, 225, 1891, 1605, 1645, 679, 0, 1017, 1200 },
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{ 2145, 357, 1453, 1280, 586, 887, 1114, 2300, 653, 1272, 1017, 0, 504 },
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{ 1972, 579, 1260, 987, 371, 999, 701, 2099, 600, 1162, 1200, 504, 0 },
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};
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public int VehicleNumber = 1;
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public int Depot = 0;
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};
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// [END data_model]
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// [START solution_printer]
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/// <summary>
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/// Print the solution.
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/// </summary>
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static void PrintSolution(in RoutingModel routing, in RoutingIndexManager manager, in Assignment solution)
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{
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Console.WriteLine("Objective: {0} miles", solution.ObjectiveValue());
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// Inspect solution.
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Console.WriteLine("Route:");
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long routeDistance = 0;
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var index = routing.Start(0);
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while (routing.IsEnd(index) == false)
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{
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Console.Write("{0} -> ", manager.IndexToNode((int)index));
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var previousIndex = index;
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index = solution.Value(routing.NextVar(index));
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routeDistance += routing.GetArcCostForVehicle(previousIndex, index, 0);
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}
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Console.WriteLine("{0}", manager.IndexToNode((int)index));
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Console.WriteLine("Route distance: {0}miles", routeDistance);
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}
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// [END solution_printer]
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public static void Main(String[] args)
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{
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// Instantiate the data problem.
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// [START data]
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DataModel data = new DataModel();
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// [END data]
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// Create Routing Index Manager
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// [START index_manager]
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RoutingIndexManager manager =
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new RoutingIndexManager(data.DistanceMatrix.GetLength(0), data.VehicleNumber, data.Depot);
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// [END index_manager]
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// Create Routing Model.
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// [START routing_model]
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RoutingModel routing = new RoutingModel(manager);
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// [END routing_model]
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// [START transit_callback]
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int transitCallbackIndex = routing.RegisterTransitCallback((long fromIndex, long toIndex) =>
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{
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// Convert from routing variable Index to
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// distance matrix NodeIndex.
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var fromNode = manager.IndexToNode(fromIndex);
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var toNode = manager.IndexToNode(toIndex);
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return data.DistanceMatrix[fromNode, toNode];
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});
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// [END transit_callback]
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// Define cost of each arc.
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// [START arc_cost]
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routing.SetArcCostEvaluatorOfAllVehicles(transitCallbackIndex);
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// [END arc_cost]
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// Setting first solution heuristic.
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// [START parameters]
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RoutingSearchParameters searchParameters =
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operations_research_constraint_solver.DefaultRoutingSearchParameters();
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searchParameters.FirstSolutionStrategy = FirstSolutionStrategy.Types.Value.PathCheapestArc;
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// [END parameters]
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// Solve the problem.
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// [START solve]
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Assignment solution = routing.SolveWithParameters(searchParameters);
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// [END solve]
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// Print solution on console.
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// [START print_solution]
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PrintSolution(routing, manager, solution);
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// [END print_solution]
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}
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}
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// [END program]
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