routing_index_manager.h

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// Copyright 2010-2025 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.
 
#ifndef ORTOOLS_CONSTRAINT_SOLVER_ROUTING_INDEX_MANAGER_H_
#define ORTOOLS_CONSTRAINT_SOLVER_ROUTING_INDEX_MANAGER_H_
 
#include <cstdint>
#include <utility>
#include <vector>
 
#include "absl/log/check.h"
#include "absl/types/span.h"
#include "ortools/base/base_export.h"
#include "ortools/base/strong_vector.h"
#include "ortools/constraint_solver/routing_types.h"
 
namespace operations_research {

class OR_DLL RoutingIndexManager {
 public:
  typedef RoutingNodeIndex NodeIndex;
  static const int64_t kUnassigned;

  RoutingIndexManager(int num_nodes, int num_vehicles, NodeIndex depot);
  RoutingIndexManager(int num_nodes, int num_vehicles,
                      const std::vector<NodeIndex>& starts,
                      const std::vector<NodeIndex>& ends);
  RoutingIndexManager(
      int num_nodes, int num_vehicles,
      const std::vector<std::pair<NodeIndex, NodeIndex> >& starts_ends);
 
  // Returns the number of nodes in the manager.
  int num_nodes() const { return num_nodes_; }
  // Returns the number of vehicles in the manager.
  int num_vehicles() const { return num_vehicles_; }
  // Returns the number of indices mapped to nodes.
  int num_indices() const { return index_to_node_.size(); }
  // Returns start and end indices of the given vehicle.
  int64_t GetStartIndex(int vehicle) const {
    return vehicle_to_start_[vehicle];
  }
  int64_t GetEndIndex(int vehicle) const { return vehicle_to_end_[vehicle]; }
  // Returns the index of a node. A node can correspond to multiple indices if
  // it's a start or end node. As of 03/2020, kUnassigned will be returned for
  // all end nodes. If a node appears more than once as a start node, the index
  // of the first node in the list of start nodes is returned.
  int64_t NodeToIndex(NodeIndex node) const {
    DCHECK_GE(node.value(), 0);
    DCHECK_LT(node.value(), node_to_index_.size());
    return node_to_index_[node];
  }
  // Same as NodeToIndex but for a given vector of nodes.
  std::vector<int64_t> NodesToIndices(
      const std::vector<NodeIndex>& nodes) const;
  // Returns the node corresponding to an index. A node may appear more than
  // once if it is used as the start or the end node of multiple vehicles.
  NodeIndex IndexToNode(int64_t index) const {
    DCHECK_GE(index, 0);
    DCHECK_LT(index, index_to_node_.size());
    return index_to_node_[index];
  }
  // Same as IndexToNode but for a given vector of indices.
  std::vector<NodeIndex> IndicesToNodes(
      absl::Span<const int64_t> indices) const;
  // TODO(user) Add unit tests for NodesToIndices and IndicesToNodes.
  // TODO(user): Remove when removal of NodeIndex from RoutingModel is
  // complete.
  int num_unique_depots() const { return num_unique_depots_; }
  std::vector<NodeIndex> GetIndexToNodeMap() const { return index_to_node_; }
 
 private:
  void Initialize(
      int num_nodes, int num_vehicles,
      const std::vector<std::pair<NodeIndex, NodeIndex> >& starts_ends);
 
  std::vector<NodeIndex> index_to_node_;
  util_intops::StrongVector<NodeIndex, int64_t> node_to_index_;
  std::vector<int64_t> vehicle_to_start_;
  std::vector<int64_t> vehicle_to_end_;
  int num_nodes_;
  int num_vehicles_;
  int num_unique_depots_;
};
 
}  // namespace operations_research
 
#endif  // ORTOOLS_CONSTRAINT_SOLVER_ROUTING_INDEX_MANAGER_H_