[4379] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[14185] | 3 | * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[4379] | 4 | *
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| 5 | * This file is part of HeuristicLab.
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| 6 | *
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| 7 | * HeuristicLab is free software: you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation, either version 3 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * HeuristicLab is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 | #endregion
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| 21 |
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[8053] | 22 | using System;
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| 23 | using System.Collections.Generic;
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[4379] | 24 | using HeuristicLab.Common;
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| 25 | using HeuristicLab.Core;
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| 26 | using HeuristicLab.Encodings.PermutationEncoding;
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[14927] | 27 | using HeuristicLab.Persistence;
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[4379] | 28 | using HeuristicLab.Problems.VehicleRouting.Interfaces;
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| 29 | using HeuristicLab.Problems.VehicleRouting.ProblemInstances;
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| 30 |
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| 31 | namespace HeuristicLab.Problems.VehicleRouting.Encodings.Prins {
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| 32 | [Item("PrinsEncoding", "Represents an Prins encoding of VRP solutions. It is implemented as described in Prins, C. (2004). A simple and effective evolutionary algorithm for the vehicle routing problem. Computers & Operations Research, 12:1985-2002.")]
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[14927] | 33 | [StorableType("89634df3-7e25-4a6c-861e-903310ad7819")]
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[11961] | 34 | public class PrinsEncoding : General.PermutationEncoding {
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[4379] | 35 | #region IVRPEncoding Members
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[7856] | 36 | public override int GetTourIndex(Tour tour) {
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| 37 | return 0;
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| 38 | }
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| 39 |
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[4379] | 40 | public override List<Tour> GetTours() {
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| 41 | List<Tour> result = new List<Tour>();
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| 42 |
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| 43 | int cities = ProblemInstance.Cities.Value;
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| 44 |
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| 45 | //Split permutation into vector P
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| 46 | int[] P = new int[cities + 1];
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| 47 | for (int i = 0; i <= cities; i++)
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| 48 | P[i] = -1;
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| 49 |
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| 50 | double[] V = new double[cities + 1];
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| 51 | V[0] = 0;
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| 52 | for (int i = 1; i <= cities; i++) {
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[6758] | 53 | V[i] = double.MaxValue;
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[4379] | 54 | }
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| 55 |
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| 56 | for (int i = 1; i <= cities; i++) {
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| 57 | int j = i;
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| 58 | Tour tour = new Tour();
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| 59 | bool feasible = true;
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| 60 |
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| 61 | do {
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[8053] | 62 | tour.Stops.Add(this[j - 1] + 1);
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[4379] | 63 |
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| 64 | VRPEvaluation eval =
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[6838] | 65 | ProblemInstance.EvaluateTour(tour, this);
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[4379] | 66 |
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| 67 | double cost = eval.Quality;
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[6607] | 68 | feasible = ProblemInstance.Feasible(eval);
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[4379] | 69 |
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[6710] | 70 | if (feasible || j == i) {
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[4379] | 71 | if (V[i - 1] + cost < V[j]) {
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| 72 | V[j] = V[i - 1] + cost;
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| 73 | P[j] = i - 1;
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| 74 | }
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| 75 | j++;
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| 76 | }
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| 77 |
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| 78 | } while (j <= cities && feasible);
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| 79 | }
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| 80 |
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| 81 | //extract VRP solution from vector P
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| 82 | int index = 0;
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| 83 | int index2 = cities;
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| 84 | Tour trip = null;
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| 85 | do {
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| 86 | index = P[index2];
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| 87 | trip = new Tour();
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| 88 |
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| 89 | for (int k = index + 1; k <= index2; k++) {
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| 90 | trip.Stops.Add(this[k - 1] + 1);
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| 91 | }
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| 92 |
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| 93 | if (trip.Stops.Count > 0)
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| 94 | result.Add(trip);
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| 95 |
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| 96 | index2 = index;
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| 97 | } while (index != 0);
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| 98 |
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| 99 | //if there are too many vehicles - repair
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| 100 | while (result.Count > ProblemInstance.Vehicles.Value) {
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| 101 | Tour tour = result[result.Count - 1];
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| 102 |
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| 103 | //find predecessor / successor in permutation
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| 104 | int predecessorIndex = Array.IndexOf(this.array, tour.Stops[0] - 1) - 1;
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| 105 | if (predecessorIndex >= 0) {
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| 106 | int predecessor = this[predecessorIndex] + 1;
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| 107 |
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| 108 | foreach (Tour t in result) {
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| 109 | int insertPosition = t.Stops.IndexOf(predecessor) + 1;
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| 110 | if (insertPosition != -1) {
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| 111 | t.Stops.InsertRange(insertPosition, tour.Stops);
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| 112 | break;
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| 113 | }
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| 114 | }
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| 115 | } else {
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| 116 | int successorIndex = Array.IndexOf(this.array,
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| 117 | tour.Stops[tour.Stops.Count - 1] - 1) + 1;
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| 118 | int successor = this[successorIndex] + 1;
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| 119 |
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| 120 | foreach (Tour t in result) {
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| 121 | int insertPosition = t.Stops.IndexOf(successor);
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| 122 | if (insertPosition != -1) {
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| 123 | t.Stops.InsertRange(insertPosition, tour.Stops);
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| 124 | break;
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| 125 | }
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| 126 | }
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| 127 | }
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| 128 |
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| 129 | result.Remove(tour);
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| 130 | }
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| 131 |
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| 132 | return result;
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| 133 | }
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| 134 | #endregion
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| 135 | public PrinsEncoding(Permutation permutation, IVRPProblemInstance problemInstance)
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| 136 | : base(permutation, problemInstance) {
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| 137 | }
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| 138 |
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| 139 | [StorableConstructor]
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[7906] | 140 | protected PrinsEncoding(bool serializing)
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[4379] | 141 | : base(serializing) {
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| 142 | }
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| 143 |
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[4752] | 144 | public override IDeepCloneable Clone(Cloner cloner) {
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| 145 | return new PrinsEncoding(this, cloner);
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| 146 | }
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| 147 |
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| 148 | protected PrinsEncoding(PrinsEncoding original, Cloner cloner)
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| 149 | : base(original, cloner) {
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| 150 | }
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| 151 |
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[4379] | 152 | public static PrinsEncoding ConvertFrom(IVRPEncoding encoding, IVRPProblemInstance problemInstance) {
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| 153 | List<Tour> tours = encoding.GetTours();
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| 154 | List<int> route = new List<int>();
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| 155 |
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| 156 | foreach (Tour tour in tours) {
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| 157 | foreach (int city in tour.Stops)
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| 158 | route.Add(city - 1);
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| 159 | }
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| 160 |
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| 161 | return new PrinsEncoding(
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| 162 | new Permutation(PermutationTypes.RelativeUndirected, route.ToArray()), problemInstance);
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| 163 | }
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| 164 |
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| 165 | public static PrinsEncoding ConvertFrom(List<int> routeParam, IVRPProblemInstance problemInstance) {
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| 166 | List<int> route = new List<int>(routeParam);
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| 167 |
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| 168 | while (route.Remove(0)) { //remove all delimiters (0)
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| 169 | }
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| 170 |
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| 171 | for (int i = 0; i < route.Count; i++)
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| 172 | route[i]--;
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| 173 |
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| 174 | return new PrinsEncoding(
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| 175 | new Permutation(PermutationTypes.RelativeUndirected, route.ToArray()), problemInstance);
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| 176 | }
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| 177 | }
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| 178 | }
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