routing.h

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// Copyright 2010-2021 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
// TODO(user): Add a section on costs (vehicle arc costs, span costs,
//                disjunctions costs).
//
 
#ifndef OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_H_
#define OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_H_
 
#include <algorithm>
#include <deque>
#include <functional>
#include <memory>
#include <set>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
 
#include "absl/container/flat_hash_map.h"
#include "absl/container/flat_hash_set.h"
#include "absl/functional/bind_front.h"
#include "absl/memory/memory.h"
#include "absl/time/time.h"
#include "ortools/base/int_type.h"
#include "ortools/base/integral_types.h"
#include "ortools/base/logging.h"
#include "ortools/base/macros.h"
#include "ortools/base/map_util.h"
#include "ortools/base/strong_vector.h"
#include "ortools/constraint_solver/constraint_solver.h"
#include "ortools/constraint_solver/constraint_solveri.h"
#include "ortools/constraint_solver/routing_enums.pb.h"
#include "ortools/constraint_solver/routing_index_manager.h"
#include "ortools/constraint_solver/routing_parameters.pb.h"
#include "ortools/constraint_solver/routing_types.h"
#include "ortools/graph/graph.h"
#include "ortools/sat/theta_tree.h"
#include "ortools/util/bitset.h"
#include "ortools/util/piecewise_linear_function.h"
#include "ortools/util/range_query_function.h"
#include "ortools/util/saturated_arithmetic.h"
#include "ortools/util/sorted_interval_list.h"
 
namespace operations_research {
 
class GlobalDimensionCumulOptimizer;
class LocalDimensionCumulOptimizer;
class LocalSearchPhaseParameters;
#ifndef SWIG
class IndexNeighborFinder;
class IntVarFilteredDecisionBuilder;
#endif
class RoutingDimension;
#ifndef SWIG
using util::ReverseArcListGraph;
class SweepArranger;
#endif
 
class RoutingModel {
 public:
  enum Status {
    ROUTING_NOT_SOLVED,
    ROUTING_SUCCESS,
    ROUTING_FAIL,
    ROUTING_FAIL_TIMEOUT,
    ROUTING_INVALID
  };
 
  enum PickupAndDeliveryPolicy {
    PICKUP_AND_DELIVERY_NO_ORDER,
    PICKUP_AND_DELIVERY_LIFO,
    PICKUP_AND_DELIVERY_FIFO
  };
  typedef RoutingCostClassIndex CostClassIndex;
  typedef RoutingDimensionIndex DimensionIndex;
  typedef RoutingDisjunctionIndex DisjunctionIndex;
  typedef RoutingVehicleClassIndex VehicleClassIndex;
  typedef RoutingTransitCallback1 TransitCallback1;
  typedef RoutingTransitCallback2 TransitCallback2;
 
// TODO(user): Remove all SWIG guards by adding the @ignore in .i.
#if !defined(SWIG)
  typedef RoutingIndexPair IndexPair;
  typedef RoutingIndexPairs IndexPairs;
#endif  // SWIG
 
#if !defined(SWIG)
  struct StateDependentTransit {
    RangeIntToIntFunction* transit;                   
    RangeMinMaxIndexFunction* transit_plus_identity;  
  };
  typedef std::function<StateDependentTransit(int64_t, int64_t)>
      VariableIndexEvaluator2;
#endif  // SWIG
 
#if !defined(SWIG)
  struct CostClass {
    int evaluator_index = 0;
 
 
    struct DimensionCost {
      int64_t transit_evaluator_class;
      int64_t cost_coefficient;
      const RoutingDimension* dimension;
      bool operator<(const DimensionCost& cost) const {
        if (transit_evaluator_class != cost.transit_evaluator_class) {
          return transit_evaluator_class < cost.transit_evaluator_class;
        }
        return cost_coefficient < cost.cost_coefficient;
      }
    };
    std::vector<DimensionCost>
        dimension_transit_evaluator_class_and_cost_coefficient;
 
    explicit CostClass(int evaluator_index)
        : evaluator_index(evaluator_index) {}
 
    static bool LessThan(const CostClass& a, const CostClass& b) {
      if (a.evaluator_index != b.evaluator_index) {
        return a.evaluator_index < b.evaluator_index;
      }
      return a.dimension_transit_evaluator_class_and_cost_coefficient <
             b.dimension_transit_evaluator_class_and_cost_coefficient;
    }
  };
 
  struct VehicleClass {
    CostClassIndex cost_class_index;
    int64_t fixed_cost;
    bool used_when_empty;
    // TODO(user): Find equivalent start/end nodes wrt dimensions and
    // callbacks.
    int start_equivalence_class;
    int end_equivalence_class;
    absl::StrongVector<DimensionIndex, int64_t> dimension_start_cumuls_min;
    absl::StrongVector<DimensionIndex, int64_t> dimension_start_cumuls_max;
    absl::StrongVector<DimensionIndex, int64_t> dimension_end_cumuls_min;
    absl::StrongVector<DimensionIndex, int64_t> dimension_end_cumuls_max;
    absl::StrongVector<DimensionIndex, int64_t> dimension_capacities;
    absl::StrongVector<DimensionIndex, int64_t> dimension_evaluator_classes;
    uint64_t unvisitable_nodes_fprint;
    std::vector<int> required_resource_group_indices;
 
    static bool LessThan(const VehicleClass& a, const VehicleClass& b);
  };
#endif  // defined(SWIG)
 
  struct VehicleTypeContainer {
    struct VehicleClassEntry {
      int vehicle_class;
      int64_t fixed_cost;
 
      bool operator<(const VehicleClassEntry& other) const {
        return std::tie(fixed_cost, vehicle_class) <
               std::tie(other.fixed_cost, other.vehicle_class);
      }
    };
 
    int NumTypes() const { return sorted_vehicle_classes_per_type.size(); }
 
    int Type(int vehicle) const {
      DCHECK_LT(vehicle, type_index_of_vehicle.size());
      return type_index_of_vehicle[vehicle];
    }
 
    std::vector<int> type_index_of_vehicle;
    // clang-format off
    std::vector<std::set<VehicleClassEntry> > sorted_vehicle_classes_per_type;
    std::vector<std::deque<int> > vehicles_per_vehicle_class;
    // clang-format on
  };
 
  class ResourceGroup {
   public:
    class Attributes {
     public:
      Attributes();
      Attributes(Domain start_domain, Domain end_domain);
 
      const Domain& start_domain() const { return start_domain_; }
      const Domain& end_domain() const { return end_domain_; }
 
     private:
      Domain start_domain_;
      Domain end_domain_;
    };
 
    class Resource {
     public:
      const ResourceGroup::Attributes& GetDimensionAttributes(
          const RoutingDimension* dimension) const;
 
     private:
      explicit Resource(const RoutingModel* model) : model_(model) {}
 
      void SetDimensionAttributes(ResourceGroup::Attributes attributes,
                                  const RoutingDimension* dimension);
      const ResourceGroup::Attributes& GetDefaultAttributes() const;
 
      const RoutingModel* const model_;
      absl::flat_hash_map<DimensionIndex, ResourceGroup::Attributes>
          dimension_attributes_;
 
      friend class ResourceGroup;
    };
 
    explicit ResourceGroup(const RoutingModel* model)
        : model_(model), vehicle_requires_resource_(model->vehicles(), false) {}
 
    int AddResource(Attributes attributes, const RoutingDimension* dimension);
 
    void NotifyVehicleRequiresAResource(int vehicle);
 
    const std::vector<int>& GetVehiclesRequiringAResource() const {
      return vehicles_requiring_resource_;
    }
 
    bool VehicleRequiresAResource(int vehicle) const {
      return vehicle_requires_resource_[vehicle];
    }
 
    const std::vector<Resource>& GetResources() const { return resources_; }
    const Resource& GetResource(int resource_index) const {
      DCHECK_LT(resource_index, resources_.size());
      return resources_[resource_index];
    }
    const absl::flat_hash_set<DimensionIndex>& GetAffectedDimensionIndices()
        const {
      return affected_dimension_indices_;
    }
    int Size() const { return resources_.size(); }
 
   private:
    const RoutingModel* const model_;
    std::vector<Resource> resources_;
    std::vector<bool> vehicle_requires_resource_;
    std::vector<int> vehicles_requiring_resource_;
    absl::flat_hash_set<DimensionIndex> affected_dimension_indices_;
  };
 
  static const int64_t kNoPenalty;
 
  static const DisjunctionIndex kNoDisjunction;
 
  static const DimensionIndex kNoDimension;
 
  explicit RoutingModel(const RoutingIndexManager& index_manager);
  RoutingModel(const RoutingIndexManager& index_manager,
               const RoutingModelParameters& parameters);
  ~RoutingModel();
 
  int RegisterUnaryTransitVector(std::vector<int64_t> values);
  int RegisterUnaryTransitCallback(TransitCallback1 callback);
  int RegisterPositiveUnaryTransitCallback(TransitCallback1 callback);
 
  int RegisterTransitMatrix(
      std::vector<std::vector<int64_t> /*needed_for_swig*/> values);
  int RegisterTransitCallback(TransitCallback2 callback);
  int RegisterPositiveTransitCallback(TransitCallback2 callback);
 
  int RegisterStateDependentTransitCallback(VariableIndexEvaluator2 callback);
  const TransitCallback2& TransitCallback(int callback_index) const {
    CHECK_LT(callback_index, transit_evaluators_.size());
    return transit_evaluators_[callback_index];
  }
  const TransitCallback1& UnaryTransitCallbackOrNull(int callback_index) const {
    CHECK_LT(callback_index, unary_transit_evaluators_.size());
    return unary_transit_evaluators_[callback_index];
  }
  const VariableIndexEvaluator2& StateDependentTransitCallback(
      int callback_index) const {
    CHECK_LT(callback_index, state_dependent_transit_evaluators_.size());
    return state_dependent_transit_evaluators_[callback_index];
  }
 
 
 
  bool AddDimension(int evaluator_index, int64_t slack_max, int64_t capacity,
                    bool fix_start_cumul_to_zero, const std::string& name);
  bool AddDimensionWithVehicleTransits(
      const std::vector<int>& evaluator_indices, int64_t slack_max,
      int64_t capacity, bool fix_start_cumul_to_zero, const std::string& name);
  bool AddDimensionWithVehicleCapacity(int evaluator_index, int64_t slack_max,
                                       std::vector<int64_t> vehicle_capacities,
                                       bool fix_start_cumul_to_zero,
                                       const std::string& name);
  bool AddDimensionWithVehicleTransitAndCapacity(
      const std::vector<int>& evaluator_indices, int64_t slack_max,
      std::vector<int64_t> vehicle_capacities, bool fix_start_cumul_to_zero,
      const std::string& name);
  std::pair<int, bool> AddConstantDimensionWithSlack(
      int64_t value, int64_t capacity, int64_t slack_max,
      bool fix_start_cumul_to_zero, const std::string& name);
  std::pair<int, bool> AddConstantDimension(int64_t value, int64_t capacity,
                                            bool fix_start_cumul_to_zero,
                                            const std::string& name) {
    return AddConstantDimensionWithSlack(value, capacity, 0,
                                         fix_start_cumul_to_zero, name);
  }
  std::pair<int, bool> AddVectorDimension(std::vector<int64_t> values,
                                          int64_t capacity,
                                          bool fix_start_cumul_to_zero,
                                          const std::string& name);
  std::pair<int, bool> AddMatrixDimension(
      std::vector<std::vector<int64_t> /*needed_for_swig*/> values,
      int64_t capacity, bool fix_start_cumul_to_zero, const std::string& name);
  bool AddDimensionDependentDimensionWithVehicleCapacity(
      const std::vector<int>& pure_transits,
      const std::vector<int>& dependent_transits,
      const RoutingDimension* base_dimension, int64_t slack_max,
      std::vector<int64_t> vehicle_capacities, bool fix_start_cumul_to_zero,
      const std::string& name) {
    return AddDimensionDependentDimensionWithVehicleCapacityInternal(
        pure_transits, dependent_transits, base_dimension, slack_max,
        std::move(vehicle_capacities), fix_start_cumul_to_zero, name);
  }
 
  bool AddDimensionDependentDimensionWithVehicleCapacity(
      const std::vector<int>& transits, const RoutingDimension* base_dimension,
      int64_t slack_max, std::vector<int64_t> vehicle_capacities,
      bool fix_start_cumul_to_zero, const std::string& name);
  bool AddDimensionDependentDimensionWithVehicleCapacity(
      int transit, const RoutingDimension* base_dimension, int64_t slack_max,
      int64_t vehicle_capacity, bool fix_start_cumul_to_zero,
      const std::string& name);
  bool AddDimensionDependentDimensionWithVehicleCapacity(
      int pure_transit, int dependent_transit,
      const RoutingDimension* base_dimension, int64_t slack_max,
      int64_t vehicle_capacity, bool fix_start_cumul_to_zero,
      const std::string& name);
 
  static RoutingModel::StateDependentTransit MakeStateDependentTransit(
      const std::function<int64_t(int64_t)>& f, int64_t domain_start,
      int64_t domain_end);
 
  Constraint* MakePathSpansAndTotalSlacks(const RoutingDimension* dimension,
                                          std::vector<IntVar*> spans,
                                          std::vector<IntVar*> total_slacks);
 
  // TODO(user): rename.
  std::vector<std::string> GetAllDimensionNames() const;
  const std::vector<RoutingDimension*>& GetDimensions() const {
    return dimensions_.get();
  }
  std::vector<RoutingDimension*> GetDimensionsWithSoftOrSpanCosts() const;
  // clang-format off
  const std::vector<std::unique_ptr<GlobalDimensionCumulOptimizer> >&
  GetGlobalDimensionCumulOptimizers() const {
    return global_dimension_optimizers_;
  }
  const std::vector<std::unique_ptr<GlobalDimensionCumulOptimizer> >&
  GetGlobalDimensionCumulMPOptimizers() const {
    return global_dimension_mp_optimizers_;
  }
  const std::vector<std::unique_ptr<LocalDimensionCumulOptimizer> >&
  GetLocalDimensionCumulOptimizers() const {
    return local_dimension_optimizers_;
  }
  const std::vector<std::unique_ptr<LocalDimensionCumulOptimizer> >&
  GetLocalDimensionCumulMPOptimizers() const {
    return local_dimension_mp_optimizers_;
  }
  // clang-format on
 
  GlobalDimensionCumulOptimizer* GetMutableGlobalCumulOptimizer(
      const RoutingDimension& dimension) const;
  GlobalDimensionCumulOptimizer* GetMutableGlobalCumulMPOptimizer(
      const RoutingDimension& dimension) const;
  LocalDimensionCumulOptimizer* GetMutableLocalCumulOptimizer(
      const RoutingDimension& dimension) const;
  LocalDimensionCumulOptimizer* GetMutableLocalCumulMPOptimizer(
      const RoutingDimension& dimension) const;
 
  bool HasDimension(const std::string& dimension_name) const;
  const RoutingDimension& GetDimensionOrDie(
      const std::string& dimension_name) const;
  RoutingDimension* GetMutableDimension(
      const std::string& dimension_name) const;
  void SetPrimaryConstrainedDimension(const std::string& dimension_name) {
    DCHECK(dimension_name.empty() || HasDimension(dimension_name));
    primary_constrained_dimension_ = dimension_name;
  }
  const std::string& GetPrimaryConstrainedDimension() const {
    return primary_constrained_dimension_;
  }
 
  int AddResourceGroup();
  // clang-format off
  const std::vector<std::unique_ptr<ResourceGroup> >& GetResourceGroups()
      const {
    return resource_groups_;
  }
  // clang-format on
  ResourceGroup* GetResourceGroup(int rg_index) const {
    DCHECK_LT(rg_index, resource_groups_.size());
    return resource_groups_[rg_index].get();
  }
 
  const std::vector<int>& GetDimensionResourceGroupIndices(
      const RoutingDimension* dimension) const;
 
  int GetDimensionResourceGroupIndex(const RoutingDimension* dimension) const {
    DCHECK_EQ(GetDimensionResourceGroupIndices(dimension).size(), 1);
    return GetDimensionResourceGroupIndices(dimension)[0];
  }
 
  DisjunctionIndex AddDisjunction(const std::vector<int64_t>& indices,
                                  int64_t penalty = kNoPenalty,
                                  int64_t max_cardinality = 1);
  const std::vector<DisjunctionIndex>& GetDisjunctionIndices(
      int64_t index) const {
    return index_to_disjunctions_[index];
  }
  template <typename F>
  void ForEachNodeInDisjunctionWithMaxCardinalityFromIndex(
      int64_t index, int64_t max_cardinality, F f) const {
    for (const DisjunctionIndex disjunction : GetDisjunctionIndices(index)) {
      if (disjunctions_[disjunction].value.max_cardinality == max_cardinality) {
        for (const int64_t d_index : disjunctions_[disjunction].indices) {
          f(d_index);
        }
      }
    }
  }
#if !defined(SWIGPYTHON)
  const std::vector<int64_t>& GetDisjunctionNodeIndices(
      DisjunctionIndex index) const {
    return disjunctions_[index].indices;
  }
#endif  // !defined(SWIGPYTHON)
  int64_t GetDisjunctionPenalty(DisjunctionIndex index) const {
    return disjunctions_[index].value.penalty;
  }
  int64_t GetDisjunctionMaxCardinality(DisjunctionIndex index) const {
    return disjunctions_[index].value.max_cardinality;
  }
  int GetNumberOfDisjunctions() const { return disjunctions_.size(); }
  bool HasMandatoryDisjunctions() const;
  bool HasMaxCardinalityConstrainedDisjunctions() const;
  std::vector<std::pair<int64_t, int64_t>> GetPerfectBinaryDisjunctions() const;
  void IgnoreDisjunctionsAlreadyForcedToZero();
 
  void AddSoftSameVehicleConstraint(const std::vector<int64_t>& indices,
                                    int64_t cost);
 
  void SetAllowedVehiclesForIndex(const std::vector<int>& vehicles,
                                  int64_t index);
 
  bool IsVehicleAllowedForIndex(int vehicle, int64_t index) {
    return allowed_vehicles_[index].empty() ||
           allowed_vehicles_[index].find(vehicle) !=
               allowed_vehicles_[index].end();
  }
 
  // TODO(user): Remove this when model introspection detects linked nodes.
  void AddPickupAndDelivery(int64_t pickup, int64_t delivery);
  void AddPickupAndDeliverySets(DisjunctionIndex pickup_disjunction,
                                DisjunctionIndex delivery_disjunction);
  // clang-format off
  const std::vector<std::pair<int, int> >&
  GetPickupIndexPairs(int64_t node_index) const;
  const std::vector<std::pair<int, int> >&
      GetDeliveryIndexPairs(int64_t node_index) const;
  // clang-format on
 
  void SetPickupAndDeliveryPolicyOfAllVehicles(PickupAndDeliveryPolicy policy);
  void SetPickupAndDeliveryPolicyOfVehicle(PickupAndDeliveryPolicy policy,
                                           int vehicle);
  PickupAndDeliveryPolicy GetPickupAndDeliveryPolicyOfVehicle(
      int vehicle) const;
 
  int GetNumOfSingletonNodes() const;
 
#ifndef SWIG
  const IndexPairs& GetPickupAndDeliveryPairs() const {
    return pickup_delivery_pairs_;
  }
  const std::vector<std::pair<DisjunctionIndex, DisjunctionIndex>>&
  GetPickupAndDeliveryDisjunctions() const {
    return pickup_delivery_disjunctions_;
  }
  const IndexPairs& GetImplicitUniquePickupAndDeliveryPairs() const {
    DCHECK(closed_);
    return implicit_pickup_delivery_pairs_without_alternatives_;
  }
#endif  // SWIG
  enum VisitTypePolicy {
    TYPE_ADDED_TO_VEHICLE,
    ADDED_TYPE_REMOVED_FROM_VEHICLE,
    TYPE_ON_VEHICLE_UP_TO_VISIT,
    TYPE_SIMULTANEOUSLY_ADDED_AND_REMOVED
  };
  // TODO(user): Support multiple visit types per node?
  void SetVisitType(int64_t index, int type, VisitTypePolicy type_policy);
  int GetVisitType(int64_t index) const;
  const std::vector<int>& GetSingleNodesOfType(int type) const;
  const std::vector<int>& GetPairIndicesOfType(int type) const;
  VisitTypePolicy GetVisitTypePolicy(int64_t index) const;
  // TODO(user): Reconsider the logic and potentially remove the need to
  void CloseVisitTypes();
  int GetNumberOfVisitTypes() const { return num_visit_types_; }
#ifndef SWIG
  const std::vector<std::vector<int>>& GetTopologicallySortedVisitTypes()
      const {
    DCHECK(closed_);
    return topologically_sorted_visit_types_;
  }
#endif  // SWIG
  void AddHardTypeIncompatibility(int type1, int type2);
  void AddTemporalTypeIncompatibility(int type1, int type2);
  const absl::flat_hash_set<int>& GetHardTypeIncompatibilitiesOfType(
      int type) const;
  const absl::flat_hash_set<int>& GetTemporalTypeIncompatibilitiesOfType(
      int type) const;
  bool HasHardTypeIncompatibilities() const {
    return has_hard_type_incompatibilities_;
  }
  bool HasTemporalTypeIncompatibilities() const {
    return has_temporal_type_incompatibilities_;
  }
  void AddSameVehicleRequiredTypeAlternatives(
      int dependent_type, absl::flat_hash_set<int> required_type_alternatives);
  void AddRequiredTypeAlternativesWhenAddingType(
      int dependent_type, absl::flat_hash_set<int> required_type_alternatives);
  void AddRequiredTypeAlternativesWhenRemovingType(
      int dependent_type, absl::flat_hash_set<int> required_type_alternatives);
  // clang-format off
  const std::vector<absl::flat_hash_set<int> >&
      GetSameVehicleRequiredTypeAlternativesOfType(int type) const;
  const std::vector<absl::flat_hash_set<int> >&
      GetRequiredTypeAlternativesWhenAddingType(int type) const;
  const std::vector<absl::flat_hash_set<int> >&
      GetRequiredTypeAlternativesWhenRemovingType(int type) const;
  // clang-format on
  bool HasSameVehicleTypeRequirements() const {
    return has_same_vehicle_type_requirements_;
  }
  bool HasTemporalTypeRequirements() const {
    return has_temporal_type_requirements_;
  }
 
  bool HasTypeRegulations() const {
    return HasTemporalTypeIncompatibilities() ||
           HasHardTypeIncompatibilities() || HasSameVehicleTypeRequirements() ||
           HasTemporalTypeRequirements();
  }
 
  int64_t UnperformedPenalty(int64_t var_index) const;
  int64_t UnperformedPenaltyOrValue(int64_t default_value,
                                    int64_t var_index) const;
  int64_t GetDepot() const;
 
  void SetMaximumNumberOfActiveVehicles(int max_active_vehicles) {
    max_active_vehicles_ = max_active_vehicles;
  }
  int GetMaximumNumberOfActiveVehicles() const { return max_active_vehicles_; }
  void SetArcCostEvaluatorOfAllVehicles(int evaluator_index);
  void SetArcCostEvaluatorOfVehicle(int evaluator_index, int vehicle);
  void SetFixedCostOfAllVehicles(int64_t cost);
  void SetFixedCostOfVehicle(int64_t cost, int vehicle);
  int64_t GetFixedCostOfVehicle(int vehicle) const;
 
  void SetAmortizedCostFactorsOfAllVehicles(int64_t linear_cost_factor,
                                            int64_t quadratic_cost_factor);
  void SetAmortizedCostFactorsOfVehicle(int64_t linear_cost_factor,
                                        int64_t quadratic_cost_factor,
                                        int vehicle);
 
  const std::vector<int64_t>& GetAmortizedLinearCostFactorOfVehicles() const {
    return linear_cost_factor_of_vehicle_;
  }
  const std::vector<int64_t>& GetAmortizedQuadraticCostFactorOfVehicles()
      const {
    return quadratic_cost_factor_of_vehicle_;
  }
 
  void SetVehicleUsedWhenEmpty(bool is_used, int vehicle) {
    DCHECK_LT(vehicle, vehicles_);
    vehicle_used_when_empty_[vehicle] = is_used;
  }
 
  bool IsVehicleUsedWhenEmpty(int vehicle) const {
    DCHECK_LT(vehicle, vehicles_);
    return vehicle_used_when_empty_[vehicle];
  }
 
#ifndef SWIG
  const Solver::IndexEvaluator2& first_solution_evaluator() const {
    return first_solution_evaluator_;
  }
#endif
  void SetFirstSolutionEvaluator(Solver::IndexEvaluator2 evaluator) {
    first_solution_evaluator_ = std::move(evaluator);
  }
  void AddLocalSearchOperator(LocalSearchOperator* ls_operator);
  void AddSearchMonitor(SearchMonitor* const monitor);
  void AddAtSolutionCallback(std::function<void()> callback);
  void AddVariableMinimizedByFinalizer(IntVar* var);
  void AddVariableMaximizedByFinalizer(IntVar* var);
  void AddWeightedVariableMinimizedByFinalizer(IntVar* var, int64_t cost);
  void AddVariableTargetToFinalizer(IntVar* var, int64_t target);
  void CloseModel();
  void CloseModelWithParameters(
      const RoutingSearchParameters& search_parameters);
  const Assignment* Solve(const Assignment* assignment = nullptr);
  const Assignment* SolveWithParameters(
      const RoutingSearchParameters& search_parameters,
      std::vector<const Assignment*>* solutions = nullptr);
  const Assignment* SolveFromAssignmentWithParameters(
      const Assignment* assignment,
      const RoutingSearchParameters& search_parameters,
      std::vector<const Assignment*>* solutions = nullptr);
  const Assignment* SolveFromAssignmentsWithParameters(
      const std::vector<const Assignment*>& assignments,
      const RoutingSearchParameters& search_parameters,
      std::vector<const Assignment*>* solutions = nullptr);
  void SetAssignmentFromOtherModelAssignment(
      Assignment* target_assignment, const RoutingModel* source_model,
      const Assignment* source_assignment);
  // TODO(user): Add support for non-homogeneous costs and disjunctions.
  int64_t ComputeLowerBound();
  Status status() const { return status_; }
  IntVar* ApplyLocks(const std::vector<int64_t>& locks);
  bool ApplyLocksToAllVehicles(const std::vector<std::vector<int64_t>>& locks,
                               bool close_routes);
  const Assignment* const PreAssignment() const { return preassignment_; }
  Assignment* MutablePreAssignment() { return preassignment_; }
  bool WriteAssignment(const std::string& file_name) const;
  Assignment* ReadAssignment(const std::string& file_name);
  Assignment* RestoreAssignment(const Assignment& solution);
  Assignment* ReadAssignmentFromRoutes(
      const std::vector<std::vector<int64_t>>& routes,
      bool ignore_inactive_indices);
  bool RoutesToAssignment(const std::vector<std::vector<int64_t>>& routes,
                          bool ignore_inactive_indices, bool close_routes,
                          Assignment* const assignment) const;
  void AssignmentToRoutes(
      const Assignment& assignment,
      std::vector<std::vector<int64_t>>* const routes) const;
#ifndef SWIG
  std::vector<std::vector<int64_t>> GetRoutesFromAssignment(
      const Assignment& assignment);
#endif
  Assignment* CompactAssignment(const Assignment& assignment) const;
  Assignment* CompactAndCheckAssignment(const Assignment& assignment) const;
  void AddToAssignment(IntVar* const var);
  void AddIntervalToAssignment(IntervalVar* const interval);
  const Assignment* PackCumulsOfOptimizerDimensionsFromAssignment(
      const Assignment* original_assignment, absl::Duration duration_limit);
#ifndef SWIG
  // TODO(user): Revisit if coordinates are added to the RoutingModel class.
  void SetSweepArranger(SweepArranger* sweep_arranger);
  SweepArranger* sweep_arranger() const;
#endif
  void AddLocalSearchFilter(LocalSearchFilter* filter) {
    CHECK(filter != nullptr);
    if (closed_) {
      LOG(WARNING) << "Model is closed, filter addition will be ignored.";
    }
    extra_filters_.push_back({filter, LocalSearchFilterManager::kRelax});
    extra_filters_.push_back({filter, LocalSearchFilterManager::kAccept});
  }
 
  int64_t Start(int vehicle) const { return starts_[vehicle]; }
  int64_t End(int vehicle) const { return ends_[vehicle]; }
  bool IsStart(int64_t index) const;
  bool IsEnd(int64_t index) const { return index >= Size(); }
  int VehicleIndex(int64_t index) const { return index_to_vehicle_[index]; }
  int64_t Next(const Assignment& assignment, int64_t index) const;
  bool IsVehicleUsed(const Assignment& assignment, int vehicle) const;
 
#if !defined(SWIGPYTHON)
  const std::vector<IntVar*>& Nexts() const { return nexts_; }
  const std::vector<IntVar*>& VehicleVars() const { return vehicle_vars_; }
  const std::vector<IntVar*>& ResourceVars(int resource_group) const {
    return resource_vars_[resource_group];
  }
#endif  
  IntVar* NextVar(int64_t index) const { return nexts_[index]; }
  IntVar* ActiveVar(int64_t index) const { return active_[index]; }
  IntVar* ActiveVehicleVar(int vehicle) const {
    return vehicle_active_[vehicle];
  }
  IntVar* VehicleRouteConsideredVar(int vehicle) const {
    return vehicle_route_considered_[vehicle];
  }
  IntVar* VehicleVar(int64_t index) const { return vehicle_vars_[index]; }
  IntVar* ResourceVar(int vehicle, int resource_group) const {
    DCHECK_LT(resource_group, resource_vars_.size());
    DCHECK_LT(vehicle, resource_vars_[resource_group].size());
    return resource_vars_[resource_group][vehicle];
  }
  IntVar* CostVar() const { return cost_; }
 
  int64_t GetArcCostForVehicle(int64_t from_index, int64_t to_index,
                               int64_t vehicle) const;
  bool CostsAreHomogeneousAcrossVehicles() const {
    return costs_are_homogeneous_across_vehicles_;
  }
  int64_t GetHomogeneousCost(int64_t from_index, int64_t to_index) const {
    return GetArcCostForVehicle(from_index, to_index, /*vehicle=*/0);
  }
  int64_t GetArcCostForFirstSolution(int64_t from_index,
                                     int64_t to_index) const;
  int64_t GetArcCostForClass(int64_t from_index, int64_t to_index,
                             int64_t /*CostClassIndex*/ cost_class_index) const;
  CostClassIndex GetCostClassIndexOfVehicle(int64_t vehicle) const {
    DCHECK(closed_);
    DCHECK_GE(vehicle, 0);
    DCHECK_LT(vehicle, cost_class_index_of_vehicle_.size());
    DCHECK_GE(cost_class_index_of_vehicle_[vehicle], 0);
    return cost_class_index_of_vehicle_[vehicle];
  }
  bool HasVehicleWithCostClassIndex(CostClassIndex cost_class_index) const {
    DCHECK(closed_);
    if (cost_class_index == kCostClassIndexOfZeroCost) {
      return has_vehicle_with_zero_cost_class_;
    }
    return cost_class_index < cost_classes_.size();
  }
  int GetCostClassesCount() const { return cost_classes_.size(); }
  int GetNonZeroCostClassesCount() const {
    return std::max(0, GetCostClassesCount() - 1);
  }
  VehicleClassIndex GetVehicleClassIndexOfVehicle(int64_t vehicle) const {
    DCHECK(closed_);
    return vehicle_class_index_of_vehicle_[vehicle];
  }
  int GetVehicleOfClass(VehicleClassIndex vehicle_class) const {
    DCHECK(closed_);
    const RoutingModel::VehicleTypeContainer& vehicle_type_container =
        GetVehicleTypeContainer();
    if (vehicle_class.value() >= GetVehicleClassesCount() ||
        vehicle_type_container.vehicles_per_vehicle_class[vehicle_class.value()]
            .empty()) {
      return -1;
    }
    return vehicle_type_container
        .vehicles_per_vehicle_class[vehicle_class.value()]
        .front();
  }
  int GetVehicleClassesCount() const { return vehicle_classes_.size(); }
  const std::vector<int>& GetSameVehicleIndicesOfIndex(int node) const {
    DCHECK(closed_);
    return same_vehicle_groups_[same_vehicle_group_[node]];
  }
 
  const VehicleTypeContainer& GetVehicleTypeContainer() const {
    DCHECK(closed_);
    return vehicle_type_container_;
  }
 
  bool ArcIsMoreConstrainedThanArc(int64_t from, int64_t to1, int64_t to2);
  std::string DebugOutputAssignment(
      const Assignment& solution_assignment,
      const std::string& dimension_to_print) const;
#ifndef SWIG
  std::vector<std::vector<std::pair<int64_t, int64_t>>> GetCumulBounds(
      const Assignment& solution_assignment, const RoutingDimension& dimension);
#endif
  Solver* solver() const { return solver_.get(); }
 
  bool CheckLimit() {
    DCHECK(limit_ != nullptr);
    return limit_->Check();
  }
 
  absl::Duration RemainingTime() const {
    DCHECK(limit_ != nullptr);
    return limit_->AbsoluteSolverDeadline() - solver_->Now();
  }
 
  int nodes() const { return nodes_; }
  int vehicles() const { return vehicles_; }
  int64_t Size() const { return nodes_ + vehicles_ - start_end_count_; }
 
  int64_t GetNumberOfDecisionsInFirstSolution(
      const RoutingSearchParameters& search_parameters) const;
  int64_t GetNumberOfRejectsInFirstSolution(
      const RoutingSearchParameters& search_parameters) const;
  operations_research::FirstSolutionStrategy::Value
  GetAutomaticFirstSolutionStrategy() const {
    return automatic_first_solution_strategy_;
  }
 
  bool IsMatchingModel() const;
 
#ifndef SWIG
  using GetTabuVarsCallback =
      std::function<std::vector<operations_research::IntVar*>(RoutingModel*)>;
 
  void SetTabuVarsCallback(GetTabuVarsCallback tabu_var_callback);
#endif  // SWIG
 
  // TODO(user): Find a way to test and restrict the access at the same time.
  DecisionBuilder* MakeGuidedSlackFinalizer(
      const RoutingDimension* dimension,
      std::function<int64_t(int64_t)> initializer);
#ifndef SWIG
  // TODO(user): MakeGreedyDescentLSOperator is too general for routing.h.
  static std::unique_ptr<LocalSearchOperator> MakeGreedyDescentLSOperator(
      std::vector<IntVar*> variables);
  // Read access to currently registered search monitors.
  const std::vector<SearchMonitor*>& GetSearchMonitors() const {
    return monitors_;
  }
#endif  
  DecisionBuilder* MakeSelfDependentDimensionFinalizer(
      const RoutingDimension* dimension);
 
 private:
  enum RoutingLocalSearchOperator {
    RELOCATE = 0,
    RELOCATE_PAIR,
    LIGHT_RELOCATE_PAIR,
    RELOCATE_NEIGHBORS,
    EXCHANGE,
    EXCHANGE_PAIR,
    CROSS,
    CROSS_EXCHANGE,
    TWO_OPT,
    OR_OPT,
    GLOBAL_CHEAPEST_INSERTION_CLOSE_NODES_LNS,
    LOCAL_CHEAPEST_INSERTION_CLOSE_NODES_LNS,
    GLOBAL_CHEAPEST_INSERTION_PATH_LNS,
    LOCAL_CHEAPEST_INSERTION_PATH_LNS,
    RELOCATE_PATH_GLOBAL_CHEAPEST_INSERTION_INSERT_UNPERFORMED,
    GLOBAL_CHEAPEST_INSERTION_EXPENSIVE_CHAIN_LNS,
    LOCAL_CHEAPEST_INSERTION_EXPENSIVE_CHAIN_LNS,
    RELOCATE_EXPENSIVE_CHAIN,
    LIN_KERNIGHAN,
    TSP_OPT,
    MAKE_ACTIVE,
    RELOCATE_AND_MAKE_ACTIVE,
    MAKE_ACTIVE_AND_RELOCATE,
    MAKE_INACTIVE,
    MAKE_CHAIN_INACTIVE,
    SWAP_ACTIVE,
    EXTENDED_SWAP_ACTIVE,
    NODE_PAIR_SWAP,
    PATH_LNS,
    FULL_PATH_LNS,
    TSP_LNS,
    INACTIVE_LNS,
    EXCHANGE_RELOCATE_PAIR,
    RELOCATE_SUBTRIP,
    EXCHANGE_SUBTRIP,
    LOCAL_SEARCH_OPERATOR_COUNTER
  };
 
  template <typename T>
  struct ValuedNodes {
    std::vector<int64_t> indices;
    T value;
  };
  struct DisjunctionValues {
    int64_t penalty;
    int64_t max_cardinality;
  };
  typedef ValuedNodes<DisjunctionValues> Disjunction;
 
  struct CostCacheElement {
    int index;
    CostClassIndex cost_class_index;
    int64_t cost;
  };
 
  void Initialize();
  void AddNoCycleConstraintInternal();
  bool AddDimensionWithCapacityInternal(
      const std::vector<int>& evaluator_indices, int64_t slack_max,
      std::vector<int64_t> vehicle_capacities, bool fix_start_cumul_to_zero,
      const std::string& name);
  bool AddDimensionDependentDimensionWithVehicleCapacityInternal(
      const std::vector<int>& pure_transits,
      const std::vector<int>& dependent_transits,
      const RoutingDimension* base_dimension, int64_t slack_max,
      std::vector<int64_t> vehicle_capacities, bool fix_start_cumul_to_zero,
      const std::string& name);
  bool InitializeDimensionInternal(
      const std::vector<int>& evaluator_indices,
      const std::vector<int>& state_dependent_evaluator_indices,
      int64_t slack_max, bool fix_start_cumul_to_zero,
      RoutingDimension* dimension);
  DimensionIndex GetDimensionIndex(const std::string& dimension_name) const;
 
  void StoreDimensionCumulOptimizers(const RoutingSearchParameters& parameters);
 
  void ComputeCostClasses(const RoutingSearchParameters& parameters);
  void ComputeVehicleClasses();
  void ComputeVehicleTypes();
  void FinalizeVisitTypes();
  // Called by FinalizeVisitTypes() to setup topologically_sorted_visit_types_.
  void TopologicallySortVisitTypes();
  int64_t GetArcCostForClassInternal(int64_t from_index, int64_t to_index,
                                     CostClassIndex cost_class_index) const;
  void AppendHomogeneousArcCosts(const RoutingSearchParameters& parameters,
                                 int node_index,
                                 std::vector<IntVar*>* cost_elements);
  void AppendArcCosts(const RoutingSearchParameters& parameters, int node_index,
                      std::vector<IntVar*>* cost_elements);
  Assignment* DoRestoreAssignment();
  static const CostClassIndex kCostClassIndexOfZeroCost;
  int64_t SafeGetCostClassInt64OfVehicle(int64_t vehicle) const {
    DCHECK_LT(0, vehicles_);
    return (vehicle >= 0 ? GetCostClassIndexOfVehicle(vehicle)
                         : kCostClassIndexOfZeroCost)
        .value();
  }
  int64_t GetDimensionTransitCostSum(int64_t i, int64_t j,
                                     const CostClass& cost_class) const;
  IntVar* CreateDisjunction(DisjunctionIndex disjunction);
  void AddPickupAndDeliverySetsInternal(const std::vector<int64_t>& pickups,
                                        const std::vector<int64_t>& deliveries);
  IntVar* CreateSameVehicleCost(int vehicle_index);
  int FindNextActive(int index, const std::vector<int64_t>& indices) const;
 
  bool RouteCanBeUsedByVehicle(const Assignment& assignment, int start_index,
                               int vehicle) const;
  bool ReplaceUnusedVehicle(int unused_vehicle, int active_vehicle,
                            Assignment* compact_assignment) const;
 
  void QuietCloseModel();
  void QuietCloseModelWithParameters(
      const RoutingSearchParameters& parameters) {
    if (!closed_) {
      CloseModelWithParameters(parameters);
    }
  }
 
  bool SolveMatchingModel(Assignment* assignment,
                          const RoutingSearchParameters& parameters);
#ifndef SWIG
  bool AppendAssignmentIfFeasible(
      const Assignment& assignment,
      std::vector<std::unique_ptr<Assignment>>* assignments);
#endif
  void LogSolution(const RoutingSearchParameters& parameters,
                   const std::string& description, int64_t solution_cost,
                   int64_t start_time_ms);
  Assignment* CompactAssignmentInternal(const Assignment& assignment,
                                        bool check_compact_assignment) const;
  std::string FindErrorInSearchParametersForModel(
      const RoutingSearchParameters& search_parameters) const;
  void SetupSearch(const RoutingSearchParameters& search_parameters);
  // TODO(user): Document each auxiliary method.
  Assignment* GetOrCreateAssignment();
  Assignment* GetOrCreateTmpAssignment();
  RegularLimit* GetOrCreateLimit();
  RegularLimit* GetOrCreateLocalSearchLimit();
  RegularLimit* GetOrCreateLargeNeighborhoodSearchLimit();
  RegularLimit* GetOrCreateFirstSolutionLargeNeighborhoodSearchLimit();
  LocalSearchOperator* CreateInsertionOperator();
  LocalSearchOperator* CreateMakeInactiveOperator();
  template <class T>
  LocalSearchOperator* CreateCPOperator(const T& operator_factory) {
    return operator_factory(solver_.get(), nexts_,
                            CostsAreHomogeneousAcrossVehicles()
                                ? std::vector<IntVar*>()
                                : vehicle_vars_,
                            vehicle_start_class_callback_);
  }
  template <class T>
  LocalSearchOperator* CreateCPOperator() {
    return CreateCPOperator(MakeLocalSearchOperator<T>);
  }
  template <class T, class Arg>
  LocalSearchOperator* CreateOperator(const Arg& arg) {
    return solver_->RevAlloc(new T(nexts_,
                                   CostsAreHomogeneousAcrossVehicles()
                                       ? std::vector<IntVar*>()
                                       : vehicle_vars_,
                                   vehicle_start_class_callback_, arg));
  }
  template <class T>
  LocalSearchOperator* CreatePairOperator() {
    return CreateOperator<T>(pickup_delivery_pairs_);
  }
  void CreateNeighborhoodOperators(const RoutingSearchParameters& parameters);
  LocalSearchOperator* ConcatenateOperators(
      const RoutingSearchParameters& search_parameters,
      const std::vector<LocalSearchOperator*>& operators) const;
  LocalSearchOperator* GetNeighborhoodOperators(
      const RoutingSearchParameters& search_parameters) const;
  std::vector<LocalSearchFilterManager::FilterEvent>
  GetOrCreateLocalSearchFilters(const RoutingSearchParameters& parameters,
                                bool filter_cost = true);
  LocalSearchFilterManager* GetOrCreateLocalSearchFilterManager(
      const RoutingSearchParameters& parameters);
  std::vector<LocalSearchFilterManager::FilterEvent>
  GetOrCreateFeasibilityFilters(const RoutingSearchParameters& parameters);
  LocalSearchFilterManager* GetOrCreateFeasibilityFilterManager(
      const RoutingSearchParameters& parameters);
  LocalSearchFilterManager* GetOrCreateStrongFeasibilityFilterManager(
      const RoutingSearchParameters& parameters);
  DecisionBuilder* CreateSolutionFinalizer(SearchLimit* lns_limit);
  DecisionBuilder* CreateFinalizerForMinimizedAndMaximizedVariables();
  void CreateFirstSolutionDecisionBuilders(
      const RoutingSearchParameters& search_parameters);
  DecisionBuilder* GetFirstSolutionDecisionBuilder(
      const RoutingSearchParameters& search_parameters) const;
  IntVarFilteredDecisionBuilder* GetFilteredFirstSolutionDecisionBuilderOrNull(
      const RoutingSearchParameters& parameters) const;
  LocalSearchPhaseParameters* CreateLocalSearchParameters(
      const RoutingSearchParameters& search_parameters);
  DecisionBuilder* CreateLocalSearchDecisionBuilder(
      const RoutingSearchParameters& search_parameters);
  void SetupDecisionBuilders(const RoutingSearchParameters& search_parameters);
  void SetupMetaheuristics(const RoutingSearchParameters& search_parameters);
  void SetupAssignmentCollector(
      const RoutingSearchParameters& search_parameters);
  void SetupTrace(const RoutingSearchParameters& search_parameters);
  void SetupImprovementLimit(const RoutingSearchParameters& search_parameters);
  void SetupSearchMonitors(const RoutingSearchParameters& search_parameters);
  bool UsesLightPropagation(
      const RoutingSearchParameters& search_parameters) const;
  GetTabuVarsCallback tabu_var_callback_;
 
  // Detects implicit pickup delivery pairs. These pairs are
  // non-pickup/delivery pairs for which there exists a unary dimension such
  // that the demand d of the implicit pickup is positive and the demand of the
  // implicit delivery is equal to -d.
  void DetectImplicitPickupAndDeliveries();
 
  int GetVehicleStartClass(int64_t start) const;
 
  void InitSameVehicleGroups(int number_of_groups) {
    same_vehicle_group_.assign(Size(), 0);
    same_vehicle_groups_.assign(number_of_groups, {});
  }
  void SetSameVehicleGroup(int index, int group) {
    same_vehicle_group_[index] = group;
    same_vehicle_groups_[group].push_back(index);
  }
 
  std::unique_ptr<Solver> solver_;
  int nodes_;
  int vehicles_;
  int max_active_vehicles_;
  Constraint* no_cycle_constraint_ = nullptr;
  std::vector<IntVar*> nexts_;
  std::vector<IntVar*> vehicle_vars_;
  std::vector<IntVar*> active_;
  // clang-format off
  std::vector<std::vector<IntVar*> > resource_vars_;
  // clang-format on
  // The following vectors are indexed by vehicle index.
  std::vector<IntVar*> vehicle_active_;
  std::vector<IntVar*> vehicle_route_considered_;
  std::vector<IntVar*> is_bound_to_end_;
  mutable RevSwitch is_bound_to_end_ct_added_;
  absl::flat_hash_map<std::string, DimensionIndex> dimension_name_to_index_;
  absl::StrongVector<DimensionIndex, RoutingDimension*> dimensions_;
  // clang-format off
  std::vector<std::unique_ptr<ResourceGroup> > resource_groups_;
  absl::StrongVector<DimensionIndex, std::vector<int> >
      dimension_resource_group_indices_;
 
  std::vector<std::unique_ptr<GlobalDimensionCumulOptimizer> >
      global_dimension_optimizers_;
  std::vector<std::unique_ptr<GlobalDimensionCumulOptimizer> >
      global_dimension_mp_optimizers_;
  absl::StrongVector<DimensionIndex, int> global_optimizer_index_;
  std::vector<std::unique_ptr<LocalDimensionCumulOptimizer> >
      local_dimension_optimizers_;
  std::vector<std::unique_ptr<LocalDimensionCumulOptimizer> >
      local_dimension_mp_optimizers_;
  // clang-format off
  absl::StrongVector<DimensionIndex, int> local_optimizer_index_;
  std::string primary_constrained_dimension_;
  IntVar* cost_ = nullptr;
  std::vector<int> vehicle_to_transit_cost_;
  std::vector<int64_t> fixed_cost_of_vehicle_;
  std::vector<CostClassIndex> cost_class_index_of_vehicle_;
  bool has_vehicle_with_zero_cost_class_;
  std::vector<int64_t> linear_cost_factor_of_vehicle_;
  std::vector<int64_t> quadratic_cost_factor_of_vehicle_;
  bool vehicle_amortized_cost_factors_set_;
  std::vector<bool> vehicle_used_when_empty_;
#ifndef SWIG
  absl::StrongVector<CostClassIndex, CostClass> cost_classes_;
#endif  // SWIG
  bool costs_are_homogeneous_across_vehicles_;
  bool cache_callbacks_;
  mutable std::vector<CostCacheElement> cost_cache_;  
  std::vector<VehicleClassIndex> vehicle_class_index_of_vehicle_;
#ifndef SWIG
  absl::StrongVector<VehicleClassIndex, VehicleClass> vehicle_classes_;
#endif  // SWIG
  VehicleTypeContainer vehicle_type_container_;
  std::function<int(int64_t)> vehicle_start_class_callback_;
  absl::StrongVector<DisjunctionIndex, Disjunction> disjunctions_;
  std::vector<std::vector<DisjunctionIndex> > index_to_disjunctions_;
  std::vector<ValuedNodes<int64_t> > same_vehicle_costs_;
#ifndef SWIG
  std::vector<absl::flat_hash_set<int>> allowed_vehicles_;
#endif  // SWIG
  IndexPairs pickup_delivery_pairs_;
  IndexPairs implicit_pickup_delivery_pairs_without_alternatives_;
  std::vector<std::pair<DisjunctionIndex, DisjunctionIndex> >
      pickup_delivery_disjunctions_;
  // clang-format off
  // If node_index is a pickup, index_to_pickup_index_pairs_[node_index] is the
  // vector of pairs {pair_index, pickup_index} such that
  // (pickup_delivery_pairs_[pair_index].first)[pickup_index] == node_index
  std::vector<std::vector<std::pair<int, int> > > index_to_pickup_index_pairs_;
  // Same as above for deliveries.
  std::vector<std::vector<std::pair<int, int> > >
      index_to_delivery_index_pairs_;
  // clang-format on
  std::vector<PickupAndDeliveryPolicy> vehicle_pickup_delivery_policy_;
  // Same vehicle group to which a node belongs.
  std::vector<int> same_vehicle_group_;
  // Same vehicle node groups.
  std::vector<std::vector<int>> same_vehicle_groups_;
  // Node visit types
  // Variable index to visit type index.
  std::vector<int> index_to_visit_type_;
  // Variable index to VisitTypePolicy.
  std::vector<VisitTypePolicy> index_to_type_policy_;
  // clang-format off
  std::vector<std::vector<int> > single_nodes_of_type_;
  std::vector<std::vector<int> > pair_indices_of_type_;
 
  std::vector<absl::flat_hash_set<int> >
      hard_incompatible_types_per_type_index_;
  bool has_hard_type_incompatibilities_;
  std::vector<absl::flat_hash_set<int> >
      temporal_incompatible_types_per_type_index_;
  bool has_temporal_type_incompatibilities_;
 
  std::vector<std::vector<absl::flat_hash_set<int> > >
      same_vehicle_required_type_alternatives_per_type_index_;
  bool has_same_vehicle_type_requirements_;
  std::vector<std::vector<absl::flat_hash_set<int> > >
      required_type_alternatives_when_adding_type_index_;
  std::vector<std::vector<absl::flat_hash_set<int> > >
      required_type_alternatives_when_removing_type_index_;
  bool has_temporal_type_requirements_;
  absl::flat_hash_map</*type*/int, absl::flat_hash_set<VisitTypePolicy> >
      trivially_infeasible_visit_types_to_policies_;
 
  // Visit types sorted topologically based on required-->dependent requirement
  // arcs between the types (if the requirement/dependency graph is acyclic).
  // Visit types of the same topological level are sorted in each sub-vector
  // by decreasing requirement "tightness", computed as the pair of the two
  // following criteria:
  //
  // 1) How highly *dependent* this type is, determined by
  //    (total number of required alternative sets for that type)
  //        / (average number of types in the required alternative sets)
  // 2) How highly *required* this type t is, computed as
  //    SUM_{S required set containing t} ( 1 / |S| ),
  //    i.e. the sum of reverse number of elements of all required sets
  //    containing the type t.
  //
  // The higher these two numbers, the tighter the type is wrt requirements.
  std::vector<std::vector<int> > topologically_sorted_visit_types_;
  // clang-format on
  int num_visit_types_;
  // Two indices are equivalent if they correspond to the same node (as given
  // to the constructors taking a RoutingIndexManager).
  std::vector<int> index_to_equivalence_class_;
  std::vector<int> index_to_vehicle_;
  std::vector<int64_t> starts_;
  std::vector<int64_t> ends_;
  // TODO(user): b/62478706 Once the port is done, this shouldn't be needed
  //                  anymore.
  RoutingIndexManager manager_;
  int start_end_count_;
  // Model status
  bool closed_ = false;
  Status status_ = ROUTING_NOT_SOLVED;
  bool enable_deep_serialization_ = true;
 
  // Search data
  std::vector<DecisionBuilder*> first_solution_decision_builders_;
  std::vector<IntVarFilteredDecisionBuilder*>
      first_solution_filtered_decision_builders_;
  Solver::IndexEvaluator2 first_solution_evaluator_;
  FirstSolutionStrategy::Value automatic_first_solution_strategy_ =
      FirstSolutionStrategy::UNSET;
  std::vector<LocalSearchOperator*> local_search_operators_;
  std::vector<SearchMonitor*> monitors_;
  SolutionCollector* collect_assignments_ = nullptr;
  SolutionCollector* collect_one_assignment_ = nullptr;
  SolutionCollector* packed_dimensions_assignment_collector_ = nullptr;
  DecisionBuilder* solve_db_ = nullptr;
  DecisionBuilder* improve_db_ = nullptr;
  DecisionBuilder* restore_assignment_ = nullptr;
  DecisionBuilder* restore_tmp_assignment_ = nullptr;
  Assignment* assignment_ = nullptr;
  Assignment* preassignment_ = nullptr;
  Assignment* tmp_assignment_ = nullptr;
  std::vector<IntVar*> extra_vars_;
  std::vector<IntervalVar*> extra_intervals_;
  std::vector<LocalSearchOperator*> extra_operators_;
  LocalSearchFilterManager* local_search_filter_manager_ = nullptr;
  LocalSearchFilterManager* feasibility_filter_manager_ = nullptr;
  LocalSearchFilterManager* strong_feasibility_filter_manager_ = nullptr;
  std::vector<LocalSearchFilterManager::FilterEvent> extra_filters_;
#ifndef SWIG
  std::vector<std::pair<IntVar*, int64_t>> finalizer_variable_cost_pairs_;
  std::vector<std::pair<IntVar*, int64_t>> finalizer_variable_target_pairs_;
  absl::flat_hash_map<IntVar*, int> finalizer_variable_cost_index_;
  absl::flat_hash_set<IntVar*> finalizer_variable_target_set_;
  std::unique_ptr<SweepArranger> sweep_arranger_;
#endif
 
  RegularLimit* limit_ = nullptr;
  RegularLimit* ls_limit_ = nullptr;
  RegularLimit* lns_limit_ = nullptr;
  RegularLimit* first_solution_lns_limit_ = nullptr;
 
  typedef std::pair<int64_t, int64_t> CacheKey;
  typedef absl::flat_hash_map<CacheKey, int64_t> TransitCallbackCache;
  typedef absl::flat_hash_map<CacheKey, StateDependentTransit>
      StateDependentTransitCallbackCache;
 
  std::vector<TransitCallback1> unary_transit_evaluators_;
  std::vector<TransitCallback2> transit_evaluators_;
  // The following vector stores a boolean per transit_evaluator_, indicating
  // whether the transits are all positive.
  // is_transit_evaluator_positive_ will be set to true only when registering a
  // callback via RegisterPositiveTransitCallback(), and to false otherwise.
  // The actual positivity of the transit values will only be checked in debug
  // mode, when calling RegisterPositiveTransitCallback().
  // Therefore, RegisterPositiveTransitCallback() should only be called when the
  // transits are known to be positive, as the positivity of a callback will
  // allow some improvements in the solver, but will entail in errors if the
  // transits are falsely assumed positive.
  std::vector<bool> is_transit_evaluator_positive_;
  std::vector<VariableIndexEvaluator2> state_dependent_transit_evaluators_;
  std::vector<std::unique_ptr<StateDependentTransitCallbackCache>>
      state_dependent_transit_evaluators_cache_;
 
  friend class RoutingDimension;
  friend class RoutingModelInspector;
  friend class ResourceGroup::Resource;
 
  DISALLOW_COPY_AND_ASSIGN(RoutingModel);
};
 
class RoutingModelVisitor : public BaseObject {
 public:
  static const char kLightElement[];
  static const char kLightElement2[];
  static const char kRemoveValues[];
};
 
#if !defined(SWIG)
class DisjunctivePropagator {
 public:
  struct Tasks {
    int num_chain_tasks = 0;
    std::vector<int64_t> start_min;
    std::vector<int64_t> start_max;
    std::vector<int64_t> duration_min;
    std::vector<int64_t> duration_max;
    std::vector<int64_t> end_min;
    std::vector<int64_t> end_max;
    std::vector<bool> is_preemptible;
    std::vector<const SortedDisjointIntervalList*> forbidden_intervals;
    std::vector<std::pair<int64_t, int64_t>> distance_duration;
    int64_t span_min = 0;
    int64_t span_max = kint64max;
 
    void Clear() {
      start_min.clear();
      start_max.clear();
      duration_min.clear();
      duration_max.clear();
      end_min.clear();
      end_max.clear();
      is_preemptible.clear();
      forbidden_intervals.clear();
      distance_duration.clear();
      span_min = 0;
      span_max = kint64max;
      num_chain_tasks = 0;
    }
  };
 
  bool Propagate(Tasks* tasks);
 
  bool Precedences(Tasks* tasks);
  bool MirrorTasks(Tasks* tasks);
  bool EdgeFinding(Tasks* tasks);
  bool DetectablePrecedencesWithChain(Tasks* tasks);
  bool ForbiddenIntervals(Tasks* tasks);
  bool DistanceDuration(Tasks* tasks);
  bool ChainSpanMin(Tasks* tasks);
  bool ChainSpanMinDynamic(Tasks* tasks);
 
 private:
  sat::ThetaLambdaTree<int64_t> theta_lambda_tree_;
  std::vector<int> tasks_by_start_min_;
  std::vector<int> tasks_by_end_max_;
  std::vector<int> event_of_task_;
  std::vector<int> nonchain_tasks_by_start_max_;
  std::vector<int64_t> total_duration_before_;
};
 
struct TravelBounds {
  std::vector<int64_t> min_travels;
  std::vector<int64_t> max_travels;
  std::vector<int64_t> pre_travels;
  std::vector<int64_t> post_travels;
};
 
void AppendTasksFromPath(const std::vector<int64_t>& path,
                         const TravelBounds& travel_bounds,
                         const RoutingDimension& dimension,
                         DisjunctivePropagator::Tasks* tasks);
void AppendTasksFromIntervals(const std::vector<IntervalVar*>& intervals,
                              DisjunctivePropagator::Tasks* tasks);
void FillPathEvaluation(const std::vector<int64_t>& path,
                        const RoutingModel::TransitCallback2& evaluator,
                        std::vector<int64_t>* values);
void FillTravelBoundsOfVehicle(int vehicle, const std::vector<int64_t>& path,
                               const RoutingDimension& dimension,
                               TravelBounds* travel_bounds);
#endif  // !defined(SWIG)
 
class GlobalVehicleBreaksConstraint : public Constraint {
 public:
  explicit GlobalVehicleBreaksConstraint(const RoutingDimension* dimension);
  std::string DebugString() const override {
    return "GlobalVehicleBreaksConstraint";
  }
 
  void Post() override;
  void InitialPropagate() override;
 
 private:
  void PropagateNode(int node);
  void PropagateVehicle(int vehicle);
  void PropagateMaxBreakDistance(int vehicle);
 
  const RoutingModel* model_;
  const RoutingDimension* const dimension_;
  std::vector<Demon*> vehicle_demons_;
  std::vector<int64_t> path_;
 
  void FillPartialPathOfVehicle(int vehicle);
  void FillPathTravels(const std::vector<int64_t>& path);
 
  class TaskTranslator {
   public:
    TaskTranslator(IntVar* start, int64_t before_start, int64_t after_start)
        : start_(start),
          before_start_(before_start),
          after_start_(after_start) {}
    explicit TaskTranslator(IntervalVar* interval) : interval_(interval) {}
    TaskTranslator() {}
 
    void SetStartMin(int64_t value) {
      if (start_ != nullptr) {
        start_->SetMin(CapAdd(before_start_, value));
      } else if (interval_ != nullptr) {
        interval_->SetStartMin(value);
      }
    }
    void SetStartMax(int64_t value) {
      if (start_ != nullptr) {
        start_->SetMax(CapAdd(before_start_, value));
      } else if (interval_ != nullptr) {
        interval_->SetStartMax(value);
      }
    }
    void SetDurationMin(int64_t value) {
      if (interval_ != nullptr) {
        interval_->SetDurationMin(value);
      }
    }
    void SetEndMin(int64_t value) {
      if (start_ != nullptr) {
        start_->SetMin(CapSub(value, after_start_));
      } else if (interval_ != nullptr) {
        interval_->SetEndMin(value);
      }
    }
    void SetEndMax(int64_t value) {
      if (start_ != nullptr) {
        start_->SetMax(CapSub(value, after_start_));
      } else if (interval_ != nullptr) {
        interval_->SetEndMax(value);
      }
    }
 
   private:
    IntVar* start_ = nullptr;
    int64_t before_start_;
    int64_t after_start_;
    IntervalVar* interval_ = nullptr;
  };
 
  std::vector<TaskTranslator> task_translators_;
 
  DisjunctivePropagator disjunctive_propagator_;
  DisjunctivePropagator::Tasks tasks_;
 
  TravelBounds travel_bounds_;
};
 
class TypeRegulationsChecker {
 public:
  explicit TypeRegulationsChecker(const RoutingModel& model);
  virtual ~TypeRegulationsChecker() {}
 
  bool CheckVehicle(int vehicle,
                    const std::function<int64_t(int64_t)>& next_accessor);
 
 protected:
#ifndef SWIG
  using VisitTypePolicy = RoutingModel::VisitTypePolicy;
#endif  // SWIG
 
  struct TypePolicyOccurrence {
    int num_type_added_to_vehicle = 0;
    int num_type_removed_from_vehicle = 0;
    int position_of_last_type_on_vehicle_up_to_visit = -1;
  };
 
  bool TypeOccursOnRoute(int type) const;
  bool TypeCurrentlyOnRoute(int type, int pos) const;
 
  void InitializeCheck(int vehicle,
                       const std::function<int64_t(int64_t)>& next_accessor);
  virtual void OnInitializeCheck() {}
  virtual bool HasRegulationsToCheck() const = 0;
  virtual bool CheckTypeRegulations(int type, VisitTypePolicy policy,
                                    int pos) = 0;
  virtual bool FinalizeCheck() const { return true; }
 
  const RoutingModel& model_;
 
 private:
  std::vector<TypePolicyOccurrence> occurrences_of_type_;
  std::vector<int64_t> current_route_visits_;
};
 
class TypeIncompatibilityChecker : public TypeRegulationsChecker {
 public:
  TypeIncompatibilityChecker(const RoutingModel& model,
                             bool check_hard_incompatibilities);
  ~TypeIncompatibilityChecker() override {}
 
 private:
  bool HasRegulationsToCheck() const override;
  bool CheckTypeRegulations(int type, VisitTypePolicy policy, int pos) override;
  bool check_hard_incompatibilities_;
};
 
class TypeRequirementChecker : public TypeRegulationsChecker {
 public:
  explicit TypeRequirementChecker(const RoutingModel& model)
      : TypeRegulationsChecker(model) {}
  ~TypeRequirementChecker() override {}
 
 private:
  bool HasRegulationsToCheck() const override;
  void OnInitializeCheck() override {
    types_with_same_vehicle_requirements_on_route_.clear();
  }
  // clang-format off
  bool CheckRequiredTypesCurrentlyOnRoute(
      const std::vector<absl::flat_hash_set<int> >& required_type_alternatives,
      int pos);
  // clang-format on
  bool CheckTypeRegulations(int type, VisitTypePolicy policy, int pos) override;
  bool FinalizeCheck() const override;
 
  absl::flat_hash_set<int> types_with_same_vehicle_requirements_on_route_;
};
 
class TypeRegulationsConstraint : public Constraint {
 public:
  explicit TypeRegulationsConstraint(const RoutingModel& model);
 
  void Post() override;
  void InitialPropagate() override;
 
 private:
  void PropagateNodeRegulations(int node);
  void CheckRegulationsOnVehicle(int vehicle);
 
  const RoutingModel& model_;
  TypeIncompatibilityChecker incompatibility_checker_;
  TypeRequirementChecker requirement_checker_;
  std::vector<Demon*> vehicle_demons_;
};
#if !defined SWIG
class SimpleBoundCosts {
 public:
  struct BoundCost {
    int64_t bound;
    int64_t cost;
  };
  SimpleBoundCosts(int num_bounds, BoundCost default_bound_cost)
      : bound_costs_(num_bounds, default_bound_cost) {}
  BoundCost& bound_cost(int element) { return bound_costs_[element]; }
  BoundCost bound_cost(int element) const { return bound_costs_[element]; }
  int Size() { return bound_costs_.size(); }
  SimpleBoundCosts(const SimpleBoundCosts&) = delete;
  SimpleBoundCosts operator=(const SimpleBoundCosts&) = delete;
 
 private:
  std::vector<BoundCost> bound_costs_;
};
#endif  // !defined SWIG
 
// TODO(user): Break constraints need to know the service time of nodes
class RoutingDimension {
 public:
  ~RoutingDimension();
  RoutingModel* model() const { return model_; }
  int64_t GetTransitValue(int64_t from_index, int64_t to_index,
                          int64_t vehicle) const;
  int64_t GetTransitValueFromClass(int64_t from_index, int64_t to_index,
                                   int64_t vehicle_class) const {
    return model_->TransitCallback(class_evaluators_[vehicle_class])(from_index,
                                                                     to_index);
  }
  IntVar* CumulVar(int64_t index) const { return cumuls_[index]; }
  IntVar* TransitVar(int64_t index) const { return transits_[index]; }
  IntVar* FixedTransitVar(int64_t index) const {
    return fixed_transits_[index];
  }
  IntVar* SlackVar(int64_t index) const { return slacks_[index]; }
 
#if !defined(SWIGPYTHON)
  const std::vector<IntVar*>& cumuls() const { return cumuls_; }
  const std::vector<IntVar*>& fixed_transits() const { return fixed_transits_; }
  const std::vector<IntVar*>& transits() const { return transits_; }
  const std::vector<IntVar*>& slacks() const { return slacks_; }
#if !defined(SWIGCSHARP) && !defined(SWIGJAVA)
  const std::vector<SortedDisjointIntervalList>& forbidden_intervals() const {
    return forbidden_intervals_;
  }
  SortedDisjointIntervalList GetAllowedIntervalsInRange(
      int64_t index, int64_t min_value, int64_t max_value) const;
  int64_t GetFirstPossibleGreaterOrEqualValueForNode(int64_t index,
                                                     int64_t min_value) const {
    DCHECK_LT(index, forbidden_intervals_.size());
    const SortedDisjointIntervalList& forbidden_intervals =
        forbidden_intervals_[index];
    const auto first_forbidden_interval_it =
        forbidden_intervals.FirstIntervalGreaterOrEqual(min_value);
    if (first_forbidden_interval_it != forbidden_intervals.end() &&
        min_value >= first_forbidden_interval_it->start) {
      return CapAdd(first_forbidden_interval_it->end, 1);
    }
    return min_value;
  }
  int64_t GetLastPossibleLessOrEqualValueForNode(int64_t index,
                                                 int64_t max_value) const {
    DCHECK_LT(index, forbidden_intervals_.size());
    const SortedDisjointIntervalList& forbidden_intervals =
        forbidden_intervals_[index];
    const auto last_forbidden_interval_it =
        forbidden_intervals.LastIntervalLessOrEqual(max_value);
    if (last_forbidden_interval_it != forbidden_intervals.end() &&
        max_value <= last_forbidden_interval_it->end) {
      return CapSub(last_forbidden_interval_it->start, 1);
    }
    return max_value;
  }
  const std::vector<int64_t>& vehicle_capacities() const {
    return vehicle_capacities_;
  }
  const RoutingModel::TransitCallback2& transit_evaluator(int vehicle) const {
    return model_->TransitCallback(
        class_evaluators_[vehicle_to_class_[vehicle]]);
  }
 
  const RoutingModel::TransitCallback2& class_transit_evaluator(
      RoutingVehicleClassIndex vehicle_class) const {
    const int vehicle = model_->GetVehicleOfClass(vehicle_class);
    DCHECK_NE(vehicle, -1);
    return transit_evaluator(vehicle);
  }
 
  const RoutingModel::TransitCallback1& GetUnaryTransitEvaluator(
      int vehicle) const {
    return model_->UnaryTransitCallbackOrNull(
        class_evaluators_[vehicle_to_class_[vehicle]]);
  }
  bool AreVehicleTransitsPositive(int vehicle) const {
    return model()->is_transit_evaluator_positive_
        [class_evaluators_[vehicle_to_class_[vehicle]]];
  }
  int vehicle_to_class(int vehicle) const { return vehicle_to_class_[vehicle]; }
#endif  
#endif  
  void SetSpanUpperBoundForVehicle(int64_t upper_bound, int vehicle);
  void SetSpanCostCoefficientForVehicle(int64_t coefficient, int vehicle);
  void SetSpanCostCoefficientForAllVehicles(int64_t coefficient);
  void SetGlobalSpanCostCoefficient(int64_t coefficient);
 
#ifndef SWIG
  void SetCumulVarPiecewiseLinearCost(int64_t index,
                                      const PiecewiseLinearFunction& cost);
  bool HasCumulVarPiecewiseLinearCost(int64_t index) const;
  const PiecewiseLinearFunction* GetCumulVarPiecewiseLinearCost(
      int64_t index) const;
#endif
 
  void SetCumulVarSoftUpperBound(int64_t index, int64_t upper_bound,
                                 int64_t coefficient);
  bool HasCumulVarSoftUpperBound(int64_t index) const;
  int64_t GetCumulVarSoftUpperBound(int64_t index) const;
  int64_t GetCumulVarSoftUpperBoundCoefficient(int64_t index) const;
 
  void SetCumulVarSoftLowerBound(int64_t index, int64_t lower_bound,
                                 int64_t coefficient);
  bool HasCumulVarSoftLowerBound(int64_t index) const;
  int64_t GetCumulVarSoftLowerBound(int64_t index) const;
  int64_t GetCumulVarSoftLowerBoundCoefficient(int64_t index) const;
  // TODO(user): Remove if !defined when routing.i is repaired.
#if !defined(SWIGPYTHON)
  void SetBreakIntervalsOfVehicle(std::vector<IntervalVar*> breaks, int vehicle,
                                  int pre_travel_evaluator,
                                  int post_travel_evaluator);
#endif  // !defined(SWIGPYTHON)
 
  void SetBreakIntervalsOfVehicle(std::vector<IntervalVar*> breaks, int vehicle,
                                  std::vector<int64_t> node_visit_transits);
 
  void SetBreakDistanceDurationOfVehicle(int64_t distance, int64_t duration,
                                         int vehicle);
  void InitializeBreaks();
  bool HasBreakConstraints() const;
#if !defined(SWIGPYTHON)
  void SetBreakIntervalsOfVehicle(
      std::vector<IntervalVar*> breaks, int vehicle,
      std::vector<int64_t> node_visit_transits,
      std::function<int64_t(int64_t, int64_t)> delays);
 
  const std::vector<IntervalVar*>& GetBreakIntervalsOfVehicle(
      int vehicle) const;
  // clang-format off
  const std::vector<std::pair<int64_t, int64_t> >&
      GetBreakDistanceDurationOfVehicle(int vehicle) const;
  // clang-format on
#endif  
  int GetPreTravelEvaluatorOfVehicle(int vehicle) const;
  int GetPostTravelEvaluatorOfVehicle(int vehicle) const;
 
  const RoutingDimension* base_dimension() const { return base_dimension_; }
  int64_t ShortestTransitionSlack(int64_t node) const;
 
  const std::string& name() const { return name_; }
 
#ifndef SWIG
  const ReverseArcListGraph<int, int>& GetPathPrecedenceGraph() const {
    return path_precedence_graph_;
  }
#endif  // SWIG
 
  typedef std::function<int64_t(int, int)> PickupToDeliveryLimitFunction;
 
  void SetPickupToDeliveryLimitFunctionForPair(
      PickupToDeliveryLimitFunction limit_function, int pair_index);
 
  bool HasPickupToDeliveryLimits() const;
#ifndef SWIG
  int64_t GetPickupToDeliveryLimitForPair(int pair_index, int pickup,
                                          int delivery) const;
 
  struct NodePrecedence {
    int64_t first_node;
    int64_t second_node;
    int64_t offset;
  };
 
  void AddNodePrecedence(NodePrecedence precedence) {
    node_precedences_.push_back(precedence);
  }
  const std::vector<NodePrecedence>& GetNodePrecedences() const {
    return node_precedences_;
  }
#endif  // SWIG
 
  void AddNodePrecedence(int64_t first_node, int64_t second_node,
                         int64_t offset) {
    AddNodePrecedence({first_node, second_node, offset});
  }
 
  int64_t GetSpanUpperBoundForVehicle(int vehicle) const {
    return vehicle_span_upper_bounds_[vehicle];
  }
#ifndef SWIG
  const std::vector<int64_t>& vehicle_span_upper_bounds() const {
    return vehicle_span_upper_bounds_;
  }
#endif  // SWIG
  int64_t GetSpanCostCoefficientForVehicle(int vehicle) const {
    return vehicle_span_cost_coefficients_[vehicle];
  }
#ifndef SWIG
  int64_t GetSpanCostCoefficientForVehicleClass(
      RoutingVehicleClassIndex vehicle_class) const {
    const int vehicle = model_->GetVehicleOfClass(vehicle_class);
    DCHECK_NE(vehicle, -1);
    return GetSpanCostCoefficientForVehicle(vehicle);
  }
#endif  // SWIG
#ifndef SWIG
  const std::vector<int64_t>& vehicle_span_cost_coefficients() const {
    return vehicle_span_cost_coefficients_;
  }
#endif  // SWIG
  int64_t global_span_cost_coefficient() const {
    return global_span_cost_coefficient_;
  }
 
  int64_t GetGlobalOptimizerOffset() const {
    DCHECK_GE(global_optimizer_offset_, 0);
    return global_optimizer_offset_;
  }
  int64_t GetLocalOptimizerOffsetForVehicle(int vehicle) const {
    if (vehicle >= local_optimizer_offset_for_vehicle_.size()) {
      return 0;
    }
    DCHECK_GE(local_optimizer_offset_for_vehicle_[vehicle], 0);
    return local_optimizer_offset_for_vehicle_[vehicle];
  }
#if !defined SWIG
  void SetSoftSpanUpperBoundForVehicle(SimpleBoundCosts::BoundCost bound_cost,
                                       int vehicle) {
    if (!HasSoftSpanUpperBounds()) {
      vehicle_soft_span_upper_bound_ = absl::make_unique<SimpleBoundCosts>(
          model_->vehicles(), SimpleBoundCosts::BoundCost{kint64max, 0});
    }
    vehicle_soft_span_upper_bound_->bound_cost(vehicle) = bound_cost;
  }
  bool HasSoftSpanUpperBounds() const {
    return vehicle_soft_span_upper_bound_ != nullptr;
  }
  SimpleBoundCosts::BoundCost GetSoftSpanUpperBoundForVehicle(
      int vehicle) const {
    DCHECK(HasSoftSpanUpperBounds());
    return vehicle_soft_span_upper_bound_->bound_cost(vehicle);
  }
  void SetQuadraticCostSoftSpanUpperBoundForVehicle(
      SimpleBoundCosts::BoundCost bound_cost, int vehicle) {
    if (!HasQuadraticCostSoftSpanUpperBounds()) {
      vehicle_quadratic_cost_soft_span_upper_bound_ =
          absl::make_unique<SimpleBoundCosts>(
              model_->vehicles(), SimpleBoundCosts::BoundCost{kint64max, 0});
    }
    vehicle_quadratic_cost_soft_span_upper_bound_->bound_cost(vehicle) =
        bound_cost;
  }
  bool HasQuadraticCostSoftSpanUpperBounds() const {
    return vehicle_quadratic_cost_soft_span_upper_bound_ != nullptr;
  }
  SimpleBoundCosts::BoundCost GetQuadraticCostSoftSpanUpperBoundForVehicle(
      int vehicle) const {
    DCHECK(HasQuadraticCostSoftSpanUpperBounds());
    return vehicle_quadratic_cost_soft_span_upper_bound_->bound_cost(vehicle);
  }
#endif  
 
 private:
  struct SoftBound {
    IntVar* var;
    int64_t bound;
    int64_t coefficient;
  };
 
  struct PiecewiseLinearCost {
    PiecewiseLinearCost() : var(nullptr), cost(nullptr) {}
    IntVar* var;
    std::unique_ptr<PiecewiseLinearFunction> cost;
  };
 
  class SelfBased {};
  RoutingDimension(RoutingModel* model, std::vector<int64_t> vehicle_capacities,
                   const std::string& name,
                   const RoutingDimension* base_dimension);
  RoutingDimension(RoutingModel* model, std::vector<int64_t> vehicle_capacities,
                   const std::string& name, SelfBased);
  void Initialize(const std::vector<int>& transit_evaluators,
                  const std::vector<int>& state_dependent_transit_evaluators,
                  int64_t slack_max);
  void InitializeCumuls();
  void InitializeTransits(
      const std::vector<int>& transit_evaluators,
      const std::vector<int>& state_dependent_transit_evaluators,
      int64_t slack_max);
  void InitializeTransitVariables(int64_t slack_max);
  void SetupCumulVarSoftUpperBoundCosts(
      std::vector<IntVar*>* cost_elements) const;
  void SetupCumulVarSoftLowerBoundCosts(
      std::vector<IntVar*>* cost_elements) const;
  void SetupCumulVarPiecewiseLinearCosts(
      std::vector<IntVar*>* cost_elements) const;
  void SetupGlobalSpanCost(std::vector<IntVar*>* cost_elements) const;
  void SetupSlackAndDependentTransitCosts() const;
  void CloseModel(bool use_light_propagation);
 
  void SetOffsetForGlobalOptimizer(int64_t offset) {
    global_optimizer_offset_ = std::max(Zero(), offset);
  }
  void SetVehicleOffsetsForLocalOptimizer(std::vector<int64_t> offsets) {
    std::transform(offsets.begin(), offsets.end(), offsets.begin(),
                   [](int64_t offset) { return std::max(Zero(), offset); });
    local_optimizer_offset_for_vehicle_ = std::move(offsets);
  }
 
  std::vector<IntVar*> cumuls_;
  std::vector<SortedDisjointIntervalList> forbidden_intervals_;
  std::vector<IntVar*> capacity_vars_;
  const std::vector<int64_t> vehicle_capacities_;
  std::vector<IntVar*> transits_;
  std::vector<IntVar*> fixed_transits_;
  std::vector<int> class_evaluators_;
  std::vector<int64_t> vehicle_to_class_;
#ifndef SWIG
  ReverseArcListGraph<int, int> path_precedence_graph_;
#endif
  // For every {first_node, second_node, offset} element in node_precedences_,
  // if both first_node and second_node are performed, then
  // cumuls_[second_node] must be greater than (or equal to)
  // cumuls_[first_node] + offset.
  std::vector<NodePrecedence> node_precedences_;
 
  // The transits of a dimension may depend on its cumuls or the cumuls of
  // another dimension. There can be no cycles, except for self loops, a
  // typical example for this is a time dimension.
  const RoutingDimension* const base_dimension_;
 
  // Values in state_dependent_class_evaluators_ correspond to the evaluators
  // in RoutingModel::state_dependent_transit_evaluators_ for each vehicle
  // class.
  std::vector<int> state_dependent_class_evaluators_;
  std::vector<int64_t> state_dependent_vehicle_to_class_;
 
  // For each pickup/delivery pair_index for which limits have been set,
  // pickup_to_delivery_limits_per_pair_index_[pair_index] contains the
  // PickupToDeliveryLimitFunction for the pickup and deliveries in this pair.
  std::vector<PickupToDeliveryLimitFunction>
      pickup_to_delivery_limits_per_pair_index_;
 
  // Used if some vehicle has breaks in this dimension, typically time.
  bool break_constraints_are_initialized_ = false;
  // clang-format off
  std::vector<std::vector<IntervalVar*> > vehicle_break_intervals_;
  std::vector<std::vector<std::pair<int64_t, int64_t> > >
      vehicle_break_distance_duration_;
  // clang-format on
  // For each vehicle, stores the part of travel that is made directly
  // after (before) the departure (arrival) node of the travel.
  // These parts of the travel are non-interruptible, in particular by a break.
  std::vector<int> vehicle_pre_travel_evaluators_;
  std::vector<int> vehicle_post_travel_evaluators_;
 
  std::vector<IntVar*> slacks_;
  std::vector<IntVar*> dependent_transits_;
  std::vector<int64_t> vehicle_span_upper_bounds_;
  int64_t global_span_cost_coefficient_;
  std::vector<int64_t> vehicle_span_cost_coefficients_;
  std::vector<SoftBound> cumul_var_soft_upper_bound_;
  std::vector<SoftBound> cumul_var_soft_lower_bound_;
  std::vector<PiecewiseLinearCost> cumul_var_piecewise_linear_cost_;
  RoutingModel* const model_;
  const std::string name_;
  int64_t global_optimizer_offset_;
  std::vector<int64_t> local_optimizer_offset_for_vehicle_;
  std::unique_ptr<SimpleBoundCosts> vehicle_soft_span_upper_bound_;
  std::unique_ptr<SimpleBoundCosts>
      vehicle_quadratic_cost_soft_span_upper_bound_;
  friend class RoutingModel;
  friend class RoutingModelInspector;
  friend void AppendDimensionCumulFilters(
      const std::vector<RoutingDimension*>& dimensions,
      const RoutingSearchParameters& parameters, bool filter_objective_cost,
      std::vector<LocalSearchFilterManager::FilterEvent>* filters);
 
  DISALLOW_COPY_AND_ASSIGN(RoutingDimension);
};
 
DecisionBuilder* MakeSetValuesFromTargets(Solver* solver,
                                          std::vector<IntVar*> variables,
                                          std::vector<int64_t> targets);
 
bool SolveModelWithSat(const RoutingModel& model,
                       const RoutingSearchParameters& search_parameters,
                       const Assignment* initial_solution,
                       Assignment* solution);
 
#if !defined(SWIG)
IntVarLocalSearchFilter* MakeVehicleBreaksFilter(
    const RoutingModel& routing_model, const RoutingDimension& dimension);
 
// A decision builder that monitors solutions, and tries to fix dimension
// variables whose route did not change in the candidate solution.
// Dimension variables are Cumul, Slack and break variables of all dimensions.
// The user must make sure that those variables will be always be fixed at
// solution, typically by composing another DecisionBuilder after this one.
// If this DecisionBuilder returns a non-nullptr value at some node of the
// search tree, it will always return nullptr in the subtree of that node.
// Moreover, the decision will be a simultaneous assignment of the dimension
// variables of unchanged routes on the left branch, and an empty decision on
// the right branch.
DecisionBuilder* MakeRestoreDimensionValuesForUnchangedRoutes(
    RoutingModel* model);
#endif
 
}  // namespace operations_research
#endif  // OR_TOOLS_CONSTRAINT_SOLVER_ROUTING_H_