140 lines
5.1 KiB
C++
140 lines
5.1 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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#include <cstdint>
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#include <cstdlib>
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#include <sstream>
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#include <vector>
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#include "ortools/base/logging.h"
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#include "ortools/constraint_solver/constraint_solver.h"
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#include "ortools/constraint_solver/routing.h"
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#include "ortools/constraint_solver/routing_enums.pb.h"
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#include "ortools/constraint_solver/routing_index_manager.h"
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#include "ortools/constraint_solver/routing_parameters.h"
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// [END import]
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namespace operations_research {
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// [START data_model]
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struct DataModel {
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const std::vector<std::vector<int64_t>> distance_matrix{
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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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const int num_vehicles = 1;
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const RoutingIndexManager::NodeIndex depot{0};
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};
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// [END data_model]
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// [START solution_printer]
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void PrintSolution(
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const std::vector<std::vector<RoutingIndexManager::NodeIndex>>& routes) {
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// Print routes.
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DataModel data;
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int64_t total_distance = 0;
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for (int i = 0; i < routes.size(); ++i) {
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const std::vector<RoutingIndexManager::NodeIndex>& route = routes[i];
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int64_t route_distance{0};
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std::stringstream route_text;
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LOG(INFO) << "Route for Vehicle " << i << ":";
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route_text << route[0];
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for (int j = 1; j < route.size(); ++j) {
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route_text << " -> " << route[j];
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route_distance +=
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data.distance_matrix[route[j - 1].value()][route[j].value()];
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}
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LOG(INFO) << route_text.str();
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LOG(INFO) << "Distance of the route: " << route_distance << "m";
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total_distance += route_distance;
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}
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LOG(INFO) << "Total distance of all routes: " << total_distance << "m";
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}
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// [END solution_printer]
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void Tsp() {
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// Instantiate the data problem.
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// [START data]
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DataModel data;
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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(data.distance_matrix.size(), data.num_vehicles,
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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(manager);
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// [END routing_model]
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// Define cost of each arc.
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// [START arc_cost]
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const int transit_callback_index = routing.RegisterTransitCallback(
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[&data, &manager](const int64_t from_index,
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const int64_t to_index) -> int64_t {
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// Convert from routing variable Index to distance matrix NodeIndex.
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const int from_node = manager.IndexToNode(from_index).value();
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const int to_node = manager.IndexToNode(to_index).value();
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return data.distance_matrix[from_node][to_node];
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});
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routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index);
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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 = DefaultRoutingSearchParameters();
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searchParameters.set_first_solution_strategy(
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FirstSolutionStrategy::PATH_CHEAPEST_ARC);
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// [END parameters]
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// Solve the problem.
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// [START solve]
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const Assignment* solution = routing.SolveWithParameters(searchParameters);
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// [END solve]
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// [START get_routes]
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// Get the routes and convert indices to nodes.
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std::vector<std::vector<RoutingIndexManager::NodeIndex>> routes;
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for (const std::vector<int64_t>& route_indices :
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routing.GetRoutesFromAssignment(*solution)) {
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routes.push_back(manager.IndicesToNodes(route_indices));
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}
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// [END get_routes]
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// Print solution on console.
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PrintSolution(routes);
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// [END print_solution]
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}
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} // namespace operations_research
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int main(int /*argc*/, char* /*argv*/[]) {
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operations_research::Tsp();
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return EXIT_SUCCESS;
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}
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// [END program]
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