1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16#include <algorithm>

17#include <cstdint>

18#include <cstdlib>

19#include <sstream>

20#include <vector>

21

28

29

31

32struct DataModel {

33 const std::vector<std::vector<int64_t>> distance_matrix{

34 {0, 548, 776, 696, 582, 274, 502, 194, 308, 194, 536, 502, 388, 354, 468,

35 776, 662},

36 {548, 0, 684, 308, 194, 502, 730, 354, 696, 742, 1084, 594, 480, 674,

37 1016, 868, 1210},

38 {776, 684, 0, 992, 878, 502, 274, 810, 468, 742, 400, 1278, 1164, 1130,

39 788, 1552, 754},

40 {696, 308, 992, 0, 114, 650, 878, 502, 844, 890, 1232, 514, 628, 822,

41 1164, 560, 1358},

42 {582, 194, 878, 114, 0, 536, 764, 388, 730, 776, 1118, 400, 514, 708,

43 1050, 674, 1244},

44 {274, 502, 502, 650, 536, 0, 228, 308, 194, 240, 582, 776, 662, 628, 514,

45 1050, 708},

46 {502, 730, 274, 878, 764, 228, 0, 536, 194, 468, 354, 1004, 890, 856, 514,

47 1278, 480},

48 {194, 354, 810, 502, 388, 308, 536, 0, 342, 388, 730, 468, 354, 320, 662,

49 742, 856},

50 {308, 696, 468, 844, 730, 194, 194, 342, 0, 274, 388, 810, 696, 662, 320,

51 1084, 514},

52 {194, 742, 742, 890, 776, 240, 468, 388, 274, 0, 342, 536, 422, 388, 274,

53 810, 468},

54 {536, 1084, 400, 1232, 1118, 582, 354, 730, 388, 342, 0, 878, 764, 730,

55 388, 1152, 354},

56 {502, 594, 1278, 514, 400, 776, 1004, 468, 810, 536, 878, 0, 114, 308,

57 650, 274, 844},

58 {388, 480, 1164, 628, 514, 662, 890, 354, 696, 422, 764, 114, 0, 194, 536,

59 388, 730},

60 {354, 674, 1130, 822, 708, 628, 856, 320, 662, 388, 730, 308, 194, 0, 342,

61 422, 536},

62 {468, 1016, 788, 1164, 1050, 514, 514, 662, 320, 274, 388, 650, 536, 342,

63 0, 764, 194},

64 {776, 868, 1552, 560, 674, 1050, 1278, 742, 1084, 810, 1152, 274, 388,

65 422, 764, 0, 798},

66 {662, 1210, 754, 1358, 1244, 708, 480, 856, 514, 468, 354, 844, 730, 536,

67 194, 798, 0},

68 };

69 const int num_vehicles = 4;

70 const RoutingIndexManager::NodeIndex depot{0};

71};

72

73

79

80void PrintSolution(const DataModel& data, const RoutingIndexManager& manager,

81 const RoutingModel& routing, const Assignment& solution) {

82 int64_t max_route_distance{0};

83 for (int vehicle_id = 0; vehicle_id < data.num_vehicles; ++vehicle_id) {

84 if (!routing.IsVehicleUsed(solution, vehicle_id)) {

85 continue;

86 }

87 int64_t index = routing.Start(vehicle_id);

88 LOG(INFO) << "Route for Vehicle " << vehicle_id << ":";

89 int64_t route_distance{0};

90 std::stringstream route;

91 while (!routing.IsEnd(index)) {

92 route << manager.IndexToNode(index).value() << " -> ";

93 const int64_t previous_index = index;

94 index = solution.Value(routing.NextVar(index));

95 route_distance += routing.GetArcCostForVehicle(previous_index, index,

96 int64_t{vehicle_id});

97 }

98 LOG(INFO) << route.str() << manager.IndexToNode(index).value();

99 LOG(INFO) << "Distance of the route: " << route_distance << "m";

100 max_route_distance = std::max(route_distance, max_route_distance);

101 }

102 LOG(INFO) << "Maximum of the route distances: " << max_route_distance << "m";

103 LOG(INFO) << "";

104 LOG(INFO) << "Problem solved in " << routing.solver()->wall_time() << "ms";

105}

106

107

108void VrpGlobalSpan() {

109

110

111 DataModel data;

112

113

114

115

116 RoutingIndexManager manager(data.distance_matrix.size(), data.num_vehicles,

117 data.depot);

118

119

120

121

122 RoutingModel routing(manager);

123

124

125

126

127 const int transit_callback_index = routing.RegisterTransitCallback(

128 [&data, &manager](const int64_t from_index,

129 const int64_t to_index) -> int64_t {

130

131 const int from_node = manager.IndexToNode(from_index).value();

132 const int to_node = manager.IndexToNode(to_index).value();

133 return data.distance_matrix[from_node][to_node];

134 });

135

136

137

138

139 routing.SetArcCostEvaluatorOfAllVehicles(transit_callback_index);

140

141

142

143

144 routing.AddDimension(transit_callback_index, 0, 3000,

145 true,

146 "Distance");

147 routing.GetMutableDimension("Distance")->SetGlobalSpanCostCoefficient(100);

148

149

150

151

153 searchParameters.set_first_solution_strategy(

155

156

157

158

159 const Assignment* solution = routing.SolveWithParameters(searchParameters);

160

161

162

163

165 PrintSolution(data, manager, routing, *solution);

166 } else {

167 LOG(INFO) << "No solution found.";

168 }

169

170}

171}

172

173int main(int , char* []) {

174 operations_research::VrpGlobalSpan();

175 return EXIT_SUCCESS;

176}

177