lemon/dijkstra.h
author Peter Kovacs <kpeter@inf.elte.hu>
Sat, 30 Aug 2008 22:19:43 +0200
changeset 253 dbe309b5e855
parent 220 a5d8c039f218
parent 244 c30731a37f91
child 251 a1ffc9099c25
child 257 8d76a7bf9961
permissions -rw-r--r--
Rename BoundingBox to Box (ticket #126)
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2008
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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#ifndef LEMON_DIJKSTRA_H
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#define LEMON_DIJKSTRA_H
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///\ingroup shortest_path
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///\file
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///\brief Dijkstra algorithm.
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#include <limits>
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#include <lemon/list_graph.h>
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#include <lemon/bin_heap.h>
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#include <lemon/bits/path_dump.h>
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#include <lemon/core.h>
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#include <lemon/error.h>
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#include <lemon/maps.h>
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namespace lemon {
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  /// \brief Default operation traits for the Dijkstra algorithm class.
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  ///
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  /// This operation traits class defines all computational operations and
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  /// constants which are used in the Dijkstra algorithm.
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  template <typename Value>
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  struct DijkstraDefaultOperationTraits {
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    /// \brief Gives back the zero value of the type.
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    static Value zero() {
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      return static_cast<Value>(0);
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    }
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    /// \brief Gives back the sum of the given two elements.
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    static Value plus(const Value& left, const Value& right) {
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      return left + right;
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    }
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    /// \brief Gives back true only if the first value is less than the second.
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    static bool less(const Value& left, const Value& right) {
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      return left < right;
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    }
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  };
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  /// \brief Widest path operation traits for the Dijkstra algorithm class.
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  ///
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  /// This operation traits class defines all computational operations and
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  /// constants which are used in the Dijkstra algorithm for widest path
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  /// computation.
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  ///
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  /// \see DijkstraDefaultOperationTraits
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  template <typename Value>
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  struct DijkstraWidestPathOperationTraits {
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    /// \brief Gives back the maximum value of the type.
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    static Value zero() {
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      return std::numeric_limits<Value>::max();
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    }
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    /// \brief Gives back the minimum of the given two elements.
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    static Value plus(const Value& left, const Value& right) {
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      return std::min(left, right);
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    }
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    /// \brief Gives back true only if the first value is less than the second.
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    static bool less(const Value& left, const Value& right) {
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      return left < right;
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    }
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  };
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  ///Default traits class of Dijkstra class.
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  ///Default traits class of Dijkstra class.
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  ///\tparam GR The type of the digraph.
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  ///\tparam LM The type of the length map.
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  template<class GR, class LM>
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  struct DijkstraDefaultTraits
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  {
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    ///The type of the digraph the algorithm runs on.
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    typedef GR Digraph;
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    ///The type of the map that stores the arc lengths.
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    ///The type of the map that stores the arc lengths.
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    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.
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    typedef LM LengthMap;
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    ///The type of the length of the arcs.
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    typedef typename LM::Value Value;
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    /// Operation traits for Dijkstra algorithm.
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    /// This class defines the operations that are used in the algorithm.
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    /// \see DijkstraDefaultOperationTraits
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    typedef DijkstraDefaultOperationTraits<Value> OperationTraits;
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    /// The cross reference type used by the heap.
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    /// The cross reference type used by the heap.
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    /// Usually it is \c Digraph::NodeMap<int>.
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    typedef typename Digraph::template NodeMap<int> HeapCrossRef;
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    ///Instantiates a \ref HeapCrossRef.
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    ///This function instantiates a \ref HeapCrossRef.
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    /// \param g is the digraph, to which we would like to define the
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    /// \ref HeapCrossRef.
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    static HeapCrossRef *createHeapCrossRef(const Digraph &g)
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    {
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      return new HeapCrossRef(g);
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    }
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    ///The heap type used by the Dijkstra algorithm.
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    ///The heap type used by the Dijkstra algorithm.
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    ///
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    ///\sa BinHeap
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    ///\sa Dijkstra
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    typedef BinHeap<typename LM::Value, HeapCrossRef, std::less<Value> > Heap;
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    ///Instantiates a \ref Heap.
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    ///This function instantiates a \ref Heap.
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    static Heap *createHeap(HeapCrossRef& r)
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    {
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      return new Heap(r);
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    }
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    ///\brief The type of the map that stores the predecessor
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    ///arcs of the shortest paths.
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    ///
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    ///The type of the map that stores the predecessor
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    ///arcs of the shortest paths.
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    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
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    typedef typename Digraph::template NodeMap<typename Digraph::Arc> PredMap;
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    ///Instantiates a \ref PredMap.
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    ///This function instantiates a \ref PredMap.
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    ///\param g is the digraph, to which we would like to define the
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    ///\ref PredMap.
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    ///\todo The digraph alone may be insufficient for the initialization
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    static PredMap *createPredMap(const Digraph &g)
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    {
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      return new PredMap(g);
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    }
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    ///The type of the map that indicates which nodes are processed.
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    ///The type of the map that indicates which nodes are processed.
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    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
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    ///By default it is a NullMap.
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    ///\todo If it is set to a real map,
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    ///Dijkstra::processed() should read this.
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    typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
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    ///Instantiates a \ref ProcessedMap.
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    ///This function instantiates a \ref ProcessedMap.
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    ///\param g is the digraph, to which
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    ///we would like to define the \ref ProcessedMap
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#ifdef DOXYGEN
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    static ProcessedMap *createProcessedMap(const Digraph &g)
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#else
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    static ProcessedMap *createProcessedMap(const Digraph &)
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#endif
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    {
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      return new ProcessedMap();
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    }
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    ///The type of the map that stores the distances of the nodes.
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    ///The type of the map that stores the distances of the nodes.
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    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
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    typedef typename Digraph::template NodeMap<typename LM::Value> DistMap;
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    ///Instantiates a \ref DistMap.
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    ///This function instantiates a \ref DistMap.
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    ///\param g is the digraph, to which we would like to define
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    ///the \ref DistMap
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    static DistMap *createDistMap(const Digraph &g)
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    {
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      return new DistMap(g);
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    }
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  };
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  ///%Dijkstra algorithm class.
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  /// \ingroup shortest_path
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  ///This class provides an efficient implementation of the %Dijkstra algorithm.
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  ///
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  ///The arc lengths are passed to the algorithm using a
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  ///\ref concepts::ReadMap "ReadMap",
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  ///so it is easy to change it to any kind of length.
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  ///The type of the length is determined by the
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  ///\ref concepts::ReadMap::Value "Value" of the length map.
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  ///It is also possible to change the underlying priority heap.
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  ///
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  ///There is also a \ref dijkstra() "function type interface" for the
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  ///%Dijkstra algorithm, which is convenient in the simplier cases and
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  ///it can be used easier.
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  ///
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  ///\tparam GR The type of the digraph the algorithm runs on.
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  ///The default value is \ref ListDigraph.
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  ///The value of GR is not used directly by \ref Dijkstra, it is only
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  ///passed to \ref DijkstraDefaultTraits.
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  ///\tparam LM A readable arc map that determines the lengths of the
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  ///arcs. It is read once for each arc, so the map may involve in
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  ///relatively time consuming process to compute the arc lengths if
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  ///it is necessary. The default map type is \ref
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  ///concepts::Digraph::ArcMap "Digraph::ArcMap<int>".
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  ///The value of LM is not used directly by \ref Dijkstra, it is only
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  ///passed to \ref DijkstraDefaultTraits.
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  ///\tparam TR Traits class to set various data types used by the algorithm.
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  ///The default traits class is \ref DijkstraDefaultTraits
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  ///"DijkstraDefaultTraits<GR,LM>". See \ref DijkstraDefaultTraits
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  ///for the documentation of a Dijkstra traits class.
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#ifdef DOXYGEN
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  template <typename GR, typename LM, typename TR>
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#else
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  template <typename GR=ListDigraph,
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            typename LM=typename GR::template ArcMap<int>,
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            typename TR=DijkstraDefaultTraits<GR,LM> >
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#endif
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  class Dijkstra {
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  public:
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    ///\ref Exception for uninitialized parameters.
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    ///This error represents problems in the initialization of the
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    ///parameters of the algorithm.
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    class UninitializedParameter : public lemon::UninitializedParameter {
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    public:
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      virtual const char* what() const throw() {
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        return "lemon::Dijkstra::UninitializedParameter";
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      }
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    };
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    ///The type of the digraph the algorithm runs on.
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    typedef typename TR::Digraph Digraph;
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    ///The type of the length of the arcs.
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    typedef typename TR::LengthMap::Value Value;
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    ///The type of the map that stores the arc lengths.
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    typedef typename TR::LengthMap LengthMap;
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    ///\brief The type of the map that stores the predecessor arcs of the
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    ///shortest paths.
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    typedef typename TR::PredMap PredMap;
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    ///The type of the map that stores the distances of the nodes.
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    typedef typename TR::DistMap DistMap;
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    ///The type of the map that indicates which nodes are processed.
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    typedef typename TR::ProcessedMap ProcessedMap;
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    ///The type of the paths.
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    typedef PredMapPath<Digraph, PredMap> Path;
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    ///The cross reference type used for the current heap.
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    typedef typename TR::HeapCrossRef HeapCrossRef;
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    ///The heap type used by the algorithm.
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    typedef typename TR::Heap Heap;
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    ///The operation traits class.
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    typedef typename TR::OperationTraits OperationTraits;
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    ///The traits class.
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    typedef TR Traits;
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  private:
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    typedef typename Digraph::Node Node;
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    typedef typename Digraph::NodeIt NodeIt;
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    typedef typename Digraph::Arc Arc;
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    typedef typename Digraph::OutArcIt OutArcIt;
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    //Pointer to the underlying digraph.
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    const Digraph *G;
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    //Pointer to the length map.
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    const LengthMap *length;
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    //Pointer to the map of predecessors arcs.
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    PredMap *_pred;
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    //Indicates if _pred is locally allocated (true) or not.
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    bool local_pred;
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    //Pointer to the map of distances.
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    DistMap *_dist;
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    //Indicates if _dist is locally allocated (true) or not.
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    bool local_dist;
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    //Pointer to the map of processed status of the nodes.
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    ProcessedMap *_processed;
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    //Indicates if _processed is locally allocated (true) or not.
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    bool local_processed;
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    //Pointer to the heap cross references.
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    HeapCrossRef *_heap_cross_ref;
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    //Indicates if _heap_cross_ref is locally allocated (true) or not.
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    bool local_heap_cross_ref;
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    //Pointer to the heap.
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    Heap *_heap;
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    //Indicates if _heap is locally allocated (true) or not.
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    bool local_heap;
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    ///Creates the maps if necessary.
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    ///\todo Better memory allocation (instead of new).
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    void create_maps()
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    {
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      if(!_pred) {
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        local_pred = true;
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        _pred = Traits::createPredMap(*G);
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      }
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      if(!_dist) {
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        local_dist = true;
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        _dist = Traits::createDistMap(*G);
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      }
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      if(!_processed) {
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        local_processed = true;
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        _processed = Traits::createProcessedMap(*G);
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      }
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      if (!_heap_cross_ref) {
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        local_heap_cross_ref = true;
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        _heap_cross_ref = Traits::createHeapCrossRef(*G);
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      }
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      if (!_heap) {
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        local_heap = true;
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        _heap = Traits::createHeap(*_heap_cross_ref);
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      }
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    }
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  public:
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    typedef Dijkstra Create;
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    ///\name Named template parameters
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    ///@{
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    template <class T>
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    struct DefPredMapTraits : public Traits {
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      typedef T PredMap;
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      static PredMap *createPredMap(const Digraph &)
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      {
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        throw UninitializedParameter();
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      }
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    };
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    ///\brief \ref named-templ-param "Named parameter" for setting
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    ///\ref PredMap type.
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    ///
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    ///\ref named-templ-param "Named parameter" for setting
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    ///\ref PredMap type.
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    template <class T>
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    struct DefPredMap
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      : public Dijkstra< Digraph, LengthMap, DefPredMapTraits<T> > {
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      typedef Dijkstra< Digraph, LengthMap, DefPredMapTraits<T> > Create;
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    };
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    template <class T>
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    struct DefDistMapTraits : public Traits {
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      typedef T DistMap;
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      static DistMap *createDistMap(const Digraph &)
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      {
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        throw UninitializedParameter();
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      }
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    };
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    ///\brief \ref named-templ-param "Named parameter" for setting
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    ///\ref DistMap type.
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    ///
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    ///\ref named-templ-param "Named parameter" for setting
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    ///\ref DistMap type.
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    template <class T>
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    struct DefDistMap
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      : public Dijkstra< Digraph, LengthMap, DefDistMapTraits<T> > {
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      typedef Dijkstra< Digraph, LengthMap, DefDistMapTraits<T> > Create;
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    };
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    template <class T>
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    struct DefProcessedMapTraits : public Traits {
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      typedef T ProcessedMap;
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      static ProcessedMap *createProcessedMap(const Digraph &)
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      {
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        throw UninitializedParameter();
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      }
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    };
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    ///\brief \ref named-templ-param "Named parameter" for setting
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    ///\ref ProcessedMap type.
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    ///
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    ///\ref named-templ-param "Named parameter" for setting
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    ///\ref ProcessedMap type.
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    template <class T>
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    struct DefProcessedMap
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      : public Dijkstra< Digraph, LengthMap, DefProcessedMapTraits<T> > {
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      typedef Dijkstra< Digraph, LengthMap, DefProcessedMapTraits<T> > Create;
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    };
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    struct DefDigraphProcessedMapTraits : public Traits {
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   391
      typedef typename Digraph::template NodeMap<bool> ProcessedMap;
kpeter@244
   392
      static ProcessedMap *createProcessedMap(const Digraph &g)
alpar@100
   393
      {
kpeter@244
   394
        return new ProcessedMap(g);
alpar@100
   395
      }
alpar@100
   396
    };
kpeter@244
   397
    ///\brief \ref named-templ-param "Named parameter" for setting
kpeter@244
   398
    ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.
alpar@100
   399
    ///
kpeter@244
   400
    ///\ref named-templ-param "Named parameter" for setting
kpeter@244
   401
    ///\ref ProcessedMap type to be <tt>Digraph::NodeMap<bool></tt>.
kpeter@244
   402
    ///If you don't set it explicitly, it will be automatically allocated.
alpar@100
   403
    template <class T>
alpar@209
   404
    struct DefProcessedMapToBeDefaultMap
alpar@100
   405
      : public Dijkstra< Digraph, LengthMap, DefDigraphProcessedMapTraits> {
alpar@210
   406
      typedef Dijkstra< Digraph, LengthMap, DefDigraphProcessedMapTraits>
alpar@210
   407
      Create;
alpar@100
   408
    };
alpar@100
   409
alpar@100
   410
    template <class H, class CR>
alpar@100
   411
    struct DefHeapTraits : public Traits {
alpar@100
   412
      typedef CR HeapCrossRef;
alpar@100
   413
      typedef H Heap;
alpar@100
   414
      static HeapCrossRef *createHeapCrossRef(const Digraph &) {
alpar@209
   415
        throw UninitializedParameter();
alpar@100
   416
      }
alpar@209
   417
      static Heap *createHeap(HeapCrossRef &)
alpar@100
   418
      {
alpar@209
   419
        throw UninitializedParameter();
alpar@100
   420
      }
alpar@100
   421
    };
alpar@100
   422
    ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100
   423
    ///heap and cross reference type
alpar@100
   424
    ///
alpar@209
   425
    ///\ref named-templ-param "Named parameter" for setting heap and cross
kpeter@244
   426
    ///reference type.
alpar@100
   427
    template <class H, class CR = typename Digraph::template NodeMap<int> >
alpar@100
   428
    struct DefHeap
alpar@210
   429
      : public Dijkstra< Digraph, LengthMap, DefHeapTraits<H, CR> > {
alpar@210
   430
      typedef Dijkstra< Digraph, LengthMap, DefHeapTraits<H, CR> > Create;
alpar@100
   431
    };
alpar@100
   432
alpar@100
   433
    template <class H, class CR>
alpar@100
   434
    struct DefStandardHeapTraits : public Traits {
alpar@100
   435
      typedef CR HeapCrossRef;
alpar@100
   436
      typedef H Heap;
alpar@100
   437
      static HeapCrossRef *createHeapCrossRef(const Digraph &G) {
alpar@209
   438
        return new HeapCrossRef(G);
alpar@100
   439
      }
alpar@209
   440
      static Heap *createHeap(HeapCrossRef &R)
alpar@100
   441
      {
alpar@209
   442
        return new Heap(R);
alpar@100
   443
      }
alpar@100
   444
    };
alpar@100
   445
    ///\brief \ref named-templ-param "Named parameter" for setting
alpar@100
   446
    ///heap and cross reference type with automatic allocation
alpar@100
   447
    ///
alpar@209
   448
    ///\ref named-templ-param "Named parameter" for setting heap and cross
alpar@209
   449
    ///reference type. It can allocate the heap and the cross reference
alpar@209
   450
    ///object if the cross reference's constructor waits for the digraph as
alpar@100
   451
    ///parameter and the heap's constructor waits for the cross reference.
alpar@100
   452
    template <class H, class CR = typename Digraph::template NodeMap<int> >
alpar@100
   453
    struct DefStandardHeap
alpar@210
   454
      : public Dijkstra< Digraph, LengthMap, DefStandardHeapTraits<H, CR> > {
alpar@210
   455
      typedef Dijkstra< Digraph, LengthMap, DefStandardHeapTraits<H, CR> >
alpar@100
   456
      Create;
alpar@100
   457
    };
alpar@100
   458
alpar@100
   459
    template <class T>
alpar@100
   460
    struct DefOperationTraitsTraits : public Traits {
alpar@100
   461
      typedef T OperationTraits;
alpar@100
   462
    };
alpar@209
   463
alpar@209
   464
    /// \brief \ref named-templ-param "Named parameter" for setting
kpeter@244
   465
    ///\ref OperationTraits type
alpar@100
   466
    ///
kpeter@244
   467
    ///\ref named-templ-param "Named parameter" for setting
kpeter@244
   468
    ///\ref OperationTraits type.
alpar@100
   469
    template <class T>
alpar@100
   470
    struct DefOperationTraits
alpar@100
   471
      : public Dijkstra<Digraph, LengthMap, DefOperationTraitsTraits<T> > {
alpar@100
   472
      typedef Dijkstra<Digraph, LengthMap, DefOperationTraitsTraits<T> >
alpar@100
   473
      Create;
alpar@100
   474
    };
alpar@209
   475
alpar@100
   476
    ///@}
alpar@100
   477
alpar@100
   478
  protected:
alpar@100
   479
alpar@100
   480
    Dijkstra() {}
alpar@100
   481
alpar@209
   482
  public:
alpar@209
   483
alpar@100
   484
    ///Constructor.
alpar@209
   485
kpeter@244
   486
    ///Constructor.
kpeter@244
   487
    ///\param _g The digraph the algorithm runs on.
kpeter@244
   488
    ///\param _length The length map used by the algorithm.
kpeter@244
   489
    Dijkstra(const Digraph& _g, const LengthMap& _length) :
kpeter@244
   490
      G(&_g), length(&_length),
alpar@100
   491
      _pred(NULL), local_pred(false),
alpar@100
   492
      _dist(NULL), local_dist(false),
alpar@100
   493
      _processed(NULL), local_processed(false),
alpar@100
   494
      _heap_cross_ref(NULL), local_heap_cross_ref(false),
alpar@100
   495
      _heap(NULL), local_heap(false)
alpar@100
   496
    { }
alpar@209
   497
alpar@100
   498
    ///Destructor.
alpar@209
   499
    ~Dijkstra()
alpar@100
   500
    {
alpar@100
   501
      if(local_pred) delete _pred;
alpar@100
   502
      if(local_dist) delete _dist;
alpar@100
   503
      if(local_processed) delete _processed;
alpar@100
   504
      if(local_heap_cross_ref) delete _heap_cross_ref;
alpar@100
   505
      if(local_heap) delete _heap;
alpar@100
   506
    }
alpar@100
   507
alpar@100
   508
    ///Sets the length map.
alpar@100
   509
alpar@100
   510
    ///Sets the length map.
alpar@100
   511
    ///\return <tt> (*this) </tt>
alpar@209
   512
    Dijkstra &lengthMap(const LengthMap &m)
alpar@100
   513
    {
alpar@100
   514
      length = &m;
alpar@100
   515
      return *this;
alpar@100
   516
    }
alpar@100
   517
kpeter@244
   518
    ///Sets the map that stores the predecessor arcs.
alpar@100
   519
kpeter@244
   520
    ///Sets the map that stores the predecessor arcs.
alpar@100
   521
    ///If you don't use this function before calling \ref run(),
kpeter@244
   522
    ///it will allocate one. The destructor deallocates this
alpar@100
   523
    ///automatically allocated map, of course.
alpar@100
   524
    ///\return <tt> (*this) </tt>
alpar@209
   525
    Dijkstra &predMap(PredMap &m)
alpar@100
   526
    {
alpar@100
   527
      if(local_pred) {
alpar@209
   528
        delete _pred;
alpar@209
   529
        local_pred=false;
alpar@100
   530
      }
alpar@100
   531
      _pred = &m;
alpar@100
   532
      return *this;
alpar@100
   533
    }
alpar@100
   534
kpeter@244
   535
    ///Sets the map that indicates which nodes are processed.
alpar@100
   536
kpeter@244
   537
    ///Sets the map that indicates which nodes are processed.
alpar@100
   538
    ///If you don't use this function before calling \ref run(),
kpeter@244
   539
    ///it will allocate one. The destructor deallocates this
kpeter@244
   540
    ///automatically allocated map, of course.
kpeter@244
   541
    ///\return <tt> (*this) </tt>
kpeter@244
   542
    Dijkstra &processedMap(ProcessedMap &m)
kpeter@244
   543
    {
kpeter@244
   544
      if(local_processed) {
kpeter@244
   545
        delete _processed;
kpeter@244
   546
        local_processed=false;
kpeter@244
   547
      }
kpeter@244
   548
      _processed = &m;
kpeter@244
   549
      return *this;
kpeter@244
   550
    }
kpeter@244
   551
kpeter@244
   552
    ///Sets the map that stores the distances of the nodes.
kpeter@244
   553
kpeter@244
   554
    ///Sets the map that stores the distances of the nodes calculated by the
kpeter@244
   555
    ///algorithm.
kpeter@244
   556
    ///If you don't use this function before calling \ref run(),
kpeter@244
   557
    ///it will allocate one. The destructor deallocates this
alpar@100
   558
    ///automatically allocated map, of course.
alpar@100
   559
    ///\return <tt> (*this) </tt>
alpar@209
   560
    Dijkstra &distMap(DistMap &m)
alpar@100
   561
    {
alpar@100
   562
      if(local_dist) {
alpar@209
   563
        delete _dist;
alpar@209
   564
        local_dist=false;
alpar@100
   565
      }
alpar@100
   566
      _dist = &m;
alpar@100
   567
      return *this;
alpar@100
   568
    }
alpar@100
   569
alpar@100
   570
    ///Sets the heap and the cross reference used by algorithm.
alpar@100
   571
alpar@100
   572
    ///Sets the heap and the cross reference used by algorithm.
alpar@100
   573
    ///If you don't use this function before calling \ref run(),
kpeter@244
   574
    ///it will allocate one. The destructor deallocates this
alpar@100
   575
    ///automatically allocated heap and cross reference, of course.
alpar@100
   576
    ///\return <tt> (*this) </tt>
alpar@100
   577
    Dijkstra &heap(Heap& hp, HeapCrossRef &cr)
alpar@100
   578
    {
alpar@100
   579
      if(local_heap_cross_ref) {
alpar@209
   580
        delete _heap_cross_ref;
alpar@209
   581
        local_heap_cross_ref=false;
alpar@100
   582
      }
alpar@100
   583
      _heap_cross_ref = &cr;
alpar@100
   584
      if(local_heap) {
alpar@209
   585
        delete _heap;
alpar@209
   586
        local_heap=false;
alpar@100
   587
      }
alpar@100
   588
      _heap = &hp;
alpar@100
   589
      return *this;
alpar@100
   590
    }
alpar@100
   591
alpar@100
   592
  private:
kpeter@244
   593
alpar@100
   594
    void finalizeNodeData(Node v,Value dst)
alpar@100
   595
    {
alpar@100
   596
      _processed->set(v,true);
alpar@100
   597
      _dist->set(v, dst);
alpar@100
   598
    }
alpar@100
   599
alpar@100
   600
  public:
alpar@100
   601
alpar@100
   602
    ///\name Execution control
kpeter@244
   603
    ///The simplest way to execute the algorithm is to use one of the
kpeter@244
   604
    ///member functions called \ref lemon::Dijkstra::run() "run()".
alpar@100
   605
    ///\n
kpeter@244
   606
    ///If you need more control on the execution, first you must call
kpeter@244
   607
    ///\ref lemon::Dijkstra::init() "init()", then you can add several
kpeter@244
   608
    ///source nodes with \ref lemon::Dijkstra::addSource() "addSource()".
kpeter@244
   609
    ///Finally \ref lemon::Dijkstra::start() "start()" will perform the
kpeter@244
   610
    ///actual path computation.
alpar@100
   611
alpar@100
   612
    ///@{
alpar@100
   613
alpar@100
   614
    ///Initializes the internal data structures.
alpar@100
   615
alpar@100
   616
    ///Initializes the internal data structures.
alpar@100
   617
    ///
alpar@100
   618
    void init()
alpar@100
   619
    {
alpar@100
   620
      create_maps();
alpar@100
   621
      _heap->clear();
alpar@100
   622
      for ( NodeIt u(*G) ; u!=INVALID ; ++u ) {
alpar@209
   623
        _pred->set(u,INVALID);
alpar@209
   624
        _processed->set(u,false);
alpar@209
   625
        _heap_cross_ref->set(u,Heap::PRE_HEAP);
alpar@100
   626
      }
alpar@100
   627
    }
alpar@209
   628
alpar@100
   629
    ///Adds a new source node.
alpar@100
   630
alpar@100
   631
    ///Adds a new source node to the priority heap.
alpar@100
   632
    ///The optional second parameter is the initial distance of the node.
alpar@100
   633
    ///
kpeter@244
   634
    ///The function checks if the node has already been added to the heap and
alpar@100
   635
    ///it is pushed to the heap only if either it was not in the heap
alpar@100
   636
    ///or the shortest path found till then is shorter than \c dst.
alpar@100
   637
    void addSource(Node s,Value dst=OperationTraits::zero())
alpar@100
   638
    {
alpar@100
   639
      if(_heap->state(s) != Heap::IN_HEAP) {
alpar@209
   640
        _heap->push(s,dst);
alpar@100
   641
      } else if(OperationTraits::less((*_heap)[s], dst)) {
alpar@209
   642
        _heap->set(s,dst);
alpar@209
   643
        _pred->set(s,INVALID);
alpar@100
   644
      }
alpar@100
   645
    }
alpar@209
   646
alpar@100
   647
    ///Processes the next node in the priority heap
alpar@100
   648
alpar@100
   649
    ///Processes the next node in the priority heap.
alpar@100
   650
    ///
alpar@100
   651
    ///\return The processed node.
alpar@100
   652
    ///
kpeter@244
   653
    ///\warning The priority heap must not be empty.
alpar@100
   654
    Node processNextNode()
alpar@100
   655
    {
alpar@209
   656
      Node v=_heap->top();
alpar@100
   657
      Value oldvalue=_heap->prio();
alpar@100
   658
      _heap->pop();
alpar@100
   659
      finalizeNodeData(v,oldvalue);
alpar@209
   660
alpar@100
   661
      for(OutArcIt e(*G,v); e!=INVALID; ++e) {
alpar@209
   662
        Node w=G->target(e);
alpar@209
   663
        switch(_heap->state(w)) {
alpar@209
   664
        case Heap::PRE_HEAP:
alpar@209
   665
          _heap->push(w,OperationTraits::plus(oldvalue, (*length)[e]));
alpar@209
   666
          _pred->set(w,e);
alpar@209
   667
          break;
alpar@209
   668
        case Heap::IN_HEAP:
alpar@209
   669
          {
alpar@209
   670
            Value newvalue = OperationTraits::plus(oldvalue, (*length)[e]);
alpar@209
   671
            if ( OperationTraits::less(newvalue, (*_heap)[w]) ) {
alpar@209
   672
              _heap->decrease(w, newvalue);
alpar@209
   673
              _pred->set(w,e);
alpar@209
   674
            }
alpar@209
   675
          }
alpar@209
   676
          break;
alpar@209
   677
        case Heap::POST_HEAP:
alpar@209
   678
          break;
alpar@209
   679
        }
alpar@100
   680
      }
alpar@100
   681
      return v;
alpar@100
   682
    }
alpar@100
   683
kpeter@244
   684
    ///The next node to be processed.
alpar@209
   685
kpeter@244
   686
    ///Returns the next node to be processed or \c INVALID if the
kpeter@244
   687
    ///priority heap is empty.
kpeter@244
   688
    Node nextNode() const
alpar@209
   689
    {
alpar@100
   690
      return !_heap->empty()?_heap->top():INVALID;
alpar@100
   691
    }
alpar@209
   692
alpar@100
   693
    ///\brief Returns \c false if there are nodes
kpeter@244
   694
    ///to be processed.
alpar@100
   695
    ///
alpar@100
   696
    ///Returns \c false if there are nodes
kpeter@244
   697
    ///to be processed in the priority heap.
kpeter@244
   698
    bool emptyQueue() const { return _heap->empty(); }
kpeter@244
   699
alpar@100
   700
    ///Returns the number of the nodes to be processed in the priority heap
alpar@100
   701
kpeter@244
   702
    ///Returns the number of the nodes to be processed in the priority heap.
alpar@100
   703
    ///
kpeter@244
   704
    int queueSize() const { return _heap->size(); }
alpar@209
   705
alpar@100
   706
    ///Executes the algorithm.
alpar@100
   707
alpar@100
   708
    ///Executes the algorithm.
alpar@100
   709
    ///
kpeter@244
   710
    ///This method runs the %Dijkstra algorithm from the root node(s)
kpeter@244
   711
    ///in order to compute the shortest path to each node.
kpeter@244
   712
    ///
kpeter@244
   713
    ///The algorithm computes
kpeter@244
   714
    ///- the shortest path tree (forest),
kpeter@244
   715
    ///- the distance of each node from the root(s).
kpeter@244
   716
    ///
kpeter@244
   717
    ///\pre init() must be called and at least one root node should be
kpeter@244
   718
    ///added with addSource() before using this function.
kpeter@244
   719
    ///
kpeter@244
   720
    ///\note <tt>d.start()</tt> is just a shortcut of the following code.
kpeter@244
   721
    ///\code
kpeter@244
   722
    ///  while ( !d.emptyQueue() ) {
kpeter@244
   723
    ///    d.processNextNode();
kpeter@244
   724
    ///  }
kpeter@244
   725
    ///\endcode
kpeter@244
   726
    void start()
kpeter@244
   727
    {
kpeter@244
   728
      while ( !emptyQueue() ) processNextNode();
kpeter@244
   729
    }
kpeter@244
   730
kpeter@244
   731
    ///Executes the algorithm until the given target node is reached.
kpeter@244
   732
kpeter@244
   733
    ///Executes the algorithm until the given target node is reached.
alpar@100
   734
    ///
alpar@100
   735
    ///This method runs the %Dijkstra algorithm from the root node(s)
kpeter@244
   736
    ///in order to compute the shortest path to \c dest.
alpar@100
   737
    ///
kpeter@244
   738
    ///The algorithm computes
kpeter@244
   739
    ///- the shortest path to \c dest,
kpeter@244
   740
    ///- the distance of \c dest from the root(s).
alpar@100
   741
    ///
kpeter@244
   742
    ///\pre init() must be called and at least one root node should be
kpeter@244
   743
    ///added with addSource() before using this function.
alpar@100
   744
    void start(Node dest)
alpar@100
   745
    {
alpar@100
   746
      while ( !_heap->empty() && _heap->top()!=dest ) processNextNode();
alpar@100
   747
      if ( !_heap->empty() ) finalizeNodeData(_heap->top(),_heap->prio());
alpar@100
   748
    }
alpar@209
   749
alpar@100
   750
    ///Executes the algorithm until a condition is met.
alpar@100
   751
alpar@100
   752
    ///Executes the algorithm until a condition is met.
alpar@100
   753
    ///
kpeter@244
   754
    ///This method runs the %Dijkstra algorithm from the root node(s) in
kpeter@244
   755
    ///order to compute the shortest path to a node \c v with
kpeter@244
   756
    /// <tt>nm[v]</tt> true, if such a node can be found.
alpar@100
   757
    ///
kpeter@244
   758
    ///\param nm A \c bool (or convertible) node map. The algorithm
alpar@100
   759
    ///will stop when it reaches a node \c v with <tt>nm[v]</tt> true.
alpar@100
   760
    ///
alpar@100
   761
    ///\return The reached node \c v with <tt>nm[v]</tt> true or
alpar@100
   762
    ///\c INVALID if no such node was found.
kpeter@244
   763
    ///
kpeter@244
   764
    ///\pre init() must be called and at least one root node should be
kpeter@244
   765
    ///added with addSource() before using this function.
alpar@100
   766
    template<class NodeBoolMap>
alpar@100
   767
    Node start(const NodeBoolMap &nm)
alpar@100
   768
    {
alpar@100
   769
      while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode();
alpar@100
   770
      if ( _heap->empty() ) return INVALID;
alpar@100
   771
      finalizeNodeData(_heap->top(),_heap->prio());
alpar@100
   772
      return _heap->top();
alpar@100
   773
    }
alpar@209
   774
kpeter@244
   775
    ///Runs the algorithm from the given node.
alpar@209
   776
kpeter@244
   777
    ///This method runs the %Dijkstra algorithm from node \c s
kpeter@244
   778
    ///in order to compute the shortest path to each node.
alpar@100
   779
    ///
kpeter@244
   780
    ///The algorithm computes
kpeter@244
   781
    ///- the shortest path tree,
kpeter@244
   782
    ///- the distance of each node from the root.
kpeter@244
   783
    ///
kpeter@244
   784
    ///\note <tt>d.run(s)</tt> is just a shortcut of the following code.
alpar@100
   785
    ///\code
alpar@100
   786
    ///  d.init();
alpar@100
   787
    ///  d.addSource(s);
alpar@100
   788
    ///  d.start();
alpar@100
   789
    ///\endcode
alpar@100
   790
    void run(Node s) {
alpar@100
   791
      init();
alpar@100
   792
      addSource(s);
alpar@100
   793
      start();
alpar@100
   794
    }
alpar@209
   795
alpar@100
   796
    ///Finds the shortest path between \c s and \c t.
alpar@209
   797
kpeter@244
   798
    ///This method runs the %Dijkstra algorithm from node \c s
kpeter@244
   799
    ///in order to compute the shortest path to \c t.
alpar@100
   800
    ///
kpeter@244
   801
    ///\return The length of the shortest <tt>s</tt>--<tt>t</tt> path,
kpeter@244
   802
    ///if \c t is reachable form \c s, \c 0 otherwise.
kpeter@244
   803
    ///
kpeter@244
   804
    ///\note Apart from the return value, <tt>d.run(s,t)</tt> is just a
kpeter@244
   805
    ///shortcut of the following code.
alpar@100
   806
    ///\code
alpar@100
   807
    ///  d.init();
alpar@100
   808
    ///  d.addSource(s);
alpar@100
   809
    ///  d.start(t);
alpar@100
   810
    ///\endcode
alpar@100
   811
    Value run(Node s,Node t) {
alpar@100
   812
      init();
alpar@100
   813
      addSource(s);
alpar@100
   814
      start(t);
alpar@100
   815
      return (*_pred)[t]==INVALID?OperationTraits::zero():(*_dist)[t];
alpar@100
   816
    }
alpar@209
   817
alpar@100
   818
    ///@}
alpar@100
   819
alpar@100
   820
    ///\name Query Functions
alpar@100
   821
    ///The result of the %Dijkstra algorithm can be obtained using these
alpar@100
   822
    ///functions.\n
kpeter@244
   823
    ///Either \ref lemon::Dijkstra::run() "run()" or
kpeter@244
   824
    ///\ref lemon::Dijkstra::start() "start()" must be called before
kpeter@244
   825
    ///using them.
alpar@209
   826
alpar@100
   827
    ///@{
alpar@100
   828
kpeter@244
   829
    ///The shortest path to a node.
alpar@209
   830
kpeter@244
   831
    ///Returns the shortest path to a node.
kpeter@244
   832
    ///
kpeter@244
   833
    ///\warning \c t should be reachable from the root(s).
kpeter@244
   834
    ///
kpeter@244
   835
    ///\pre Either \ref run() or \ref start() must be called before
kpeter@244
   836
    ///using this function.
kpeter@244
   837
    Path path(Node t) const { return Path(*G, *_pred, t); }
alpar@100
   838
kpeter@244
   839
    ///The distance of a node from the root(s).
alpar@100
   840
kpeter@244
   841
    ///Returns the distance of a node from the root(s).
kpeter@244
   842
    ///
kpeter@244
   843
    ///\warning If node \c v is not reachable from the root(s), then
kpeter@244
   844
    ///the return value of this function is undefined.
kpeter@244
   845
    ///
kpeter@244
   846
    ///\pre Either \ref run() or \ref start() must be called before
kpeter@244
   847
    ///using this function.
alpar@100
   848
    Value dist(Node v) const { return (*_dist)[v]; }
alpar@100
   849
kpeter@244
   850
    ///Returns the 'previous arc' of the shortest path tree for a node.
alpar@100
   851
kpeter@244
   852
    ///This function returns the 'previous arc' of the shortest path
kpeter@244
   853
    ///tree for the node \c v, i.e. it returns the last arc of a
kpeter@244
   854
    ///shortest path from the root(s) to \c v. It is \c INVALID if \c v
kpeter@244
   855
    ///is not reachable from the root(s) or if \c v is a root.
kpeter@244
   856
    ///
kpeter@244
   857
    ///The shortest path tree used here is equal to the shortest path
kpeter@244
   858
    ///tree used in \ref predNode().
kpeter@244
   859
    ///
kpeter@244
   860
    ///\pre Either \ref run() or \ref start() must be called before
kpeter@244
   861
    ///using this function.
alpar@100
   862
    Arc predArc(Node v) const { return (*_pred)[v]; }
alpar@100
   863
kpeter@244
   864
    ///Returns the 'previous node' of the shortest path tree for a node.
alpar@100
   865
kpeter@244
   866
    ///This function returns the 'previous node' of the shortest path
kpeter@244
   867
    ///tree for the node \c v, i.e. it returns the last but one node
kpeter@244
   868
    ///from a shortest path from the root(s) to \c v. It is \c INVALID
kpeter@244
   869
    ///if \c v is not reachable from the root(s) or if \c v is a root.
kpeter@244
   870
    ///
kpeter@244
   871
    ///The shortest path tree used here is equal to the shortest path
kpeter@244
   872
    ///tree used in \ref predArc().
kpeter@244
   873
    ///
kpeter@244
   874
    ///\pre Either \ref run() or \ref start() must be called before
alpar@100
   875
    ///using this function.
alpar@100
   876
    Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
alpar@209
   877
                                  G->source((*_pred)[v]); }
alpar@209
   878
kpeter@244
   879
    ///\brief Returns a const reference to the node map that stores the
kpeter@244
   880
    ///distances of the nodes.
kpeter@244
   881
    ///
kpeter@244
   882
    ///Returns a const reference to the node map that stores the distances
kpeter@244
   883
    ///of the nodes calculated by the algorithm.
kpeter@244
   884
    ///
kpeter@244
   885
    ///\pre Either \ref run() or \ref init()
kpeter@244
   886
    ///must be called before using this function.
alpar@100
   887
    const DistMap &distMap() const { return *_dist;}
alpar@209
   888
kpeter@244
   889
    ///\brief Returns a const reference to the node map that stores the
kpeter@244
   890
    ///predecessor arcs.
kpeter@244
   891
    ///
kpeter@244
   892
    ///Returns a const reference to the node map that stores the predecessor
kpeter@244
   893
    ///arcs, which form the shortest path tree.
kpeter@244
   894
    ///
kpeter@244
   895
    ///\pre Either \ref run() or \ref init()
kpeter@244
   896
    ///must be called before using this function.
alpar@100
   897
    const PredMap &predMap() const { return *_pred;}
alpar@209
   898
kpeter@244
   899
    ///Checks if a node is reachable from the root(s).
alpar@100
   900
kpeter@244
   901
    ///Returns \c true if \c v is reachable from the root(s).
kpeter@244
   902
    ///\pre Either \ref run() or \ref start()
kpeter@244
   903
    ///must be called before using this function.
kpeter@244
   904
    bool reached(Node v) const { return (*_heap_cross_ref)[v] !=
kpeter@244
   905
                                        Heap::PRE_HEAP; }
alpar@100
   906
alpar@100
   907
    ///Checks if a node is processed.
alpar@100
   908
alpar@100
   909
    ///Returns \c true if \c v is processed, i.e. the shortest
alpar@100
   910
    ///path to \c v has already found.
kpeter@244
   911
    ///\pre Either \ref run() or \ref start()
kpeter@244
   912
    ///must be called before using this function.
kpeter@244
   913
    bool processed(Node v) const { return (*_heap_cross_ref)[v] ==
kpeter@244
   914
                                          Heap::POST_HEAP; }
kpeter@244
   915
kpeter@244
   916
    ///The current distance of a node from the root(s).
kpeter@244
   917
kpeter@244
   918
    ///Returns the current distance of a node from the root(s).
kpeter@244
   919
    ///It may be decreased in the following processes.
kpeter@244
   920
    ///\pre \c v should be reached but not processed.
kpeter@244
   921
    Value currentDist(Node v) const { return (*_heap)[v]; }
alpar@209
   922
alpar@100
   923
    ///@}
alpar@100
   924
  };
alpar@100
   925
alpar@100
   926
kpeter@244
   927
  ///Default traits class of dijkstra() function.
alpar@100
   928
kpeter@244
   929
  ///Default traits class of dijkstra() function.
kpeter@244
   930
  ///\tparam GR The type of the digraph.
kpeter@244
   931
  ///\tparam LM The type of the length map.
alpar@100
   932
  template<class GR, class LM>
alpar@100
   933
  struct DijkstraWizardDefaultTraits
alpar@100
   934
  {
kpeter@244
   935
    ///The type of the digraph the algorithm runs on.
alpar@100
   936
    typedef GR Digraph;
alpar@100
   937
    ///The type of the map that stores the arc lengths.
alpar@100
   938
alpar@100
   939
    ///The type of the map that stores the arc lengths.
alpar@100
   940
    ///It must meet the \ref concepts::ReadMap "ReadMap" concept.
alpar@100
   941
    typedef LM LengthMap;
kpeter@244
   942
    ///The type of the length of the arcs.
alpar@100
   943
    typedef typename LM::Value Value;
kpeter@244
   944
alpar@100
   945
    /// Operation traits for Dijkstra algorithm.
alpar@100
   946
kpeter@244
   947
    /// This class defines the operations that are used in the algorithm.
alpar@100
   948
    /// \see DijkstraDefaultOperationTraits
alpar@100
   949
    typedef DijkstraDefaultOperationTraits<Value> OperationTraits;
alpar@100
   950
kpeter@244
   951
    /// The cross reference type used by the heap.
alpar@100
   952
kpeter@244
   953
    /// The cross reference type used by the heap.
alpar@100
   954
    /// Usually it is \c Digraph::NodeMap<int>.
alpar@100
   955
    typedef typename Digraph::template NodeMap<int> HeapCrossRef;
kpeter@244
   956
    ///Instantiates a \ref HeapCrossRef.
alpar@100
   957
alpar@209
   958
    ///This function instantiates a \ref HeapCrossRef.
kpeter@244
   959
    /// \param g is the digraph, to which we would like to define the
alpar@100
   960
    /// HeapCrossRef.
alpar@100
   961
    /// \todo The digraph alone may be insufficient for the initialization
kpeter@244
   962
    static HeapCrossRef *createHeapCrossRef(const Digraph &g)
alpar@100
   963
    {
kpeter@244
   964
      return new HeapCrossRef(g);
alpar@100
   965
    }
alpar@209
   966
kpeter@244
   967
    ///The heap type used by the Dijkstra algorithm.
alpar@100
   968
kpeter@244
   969
    ///The heap type used by the Dijkstra algorithm.
alpar@100
   970
    ///
alpar@100
   971
    ///\sa BinHeap
alpar@100
   972
    ///\sa Dijkstra
kpeter@244
   973
    typedef BinHeap<Value, typename Digraph::template NodeMap<int>,
alpar@209
   974
                    std::less<Value> > Heap;
alpar@100
   975
kpeter@244
   976
    ///Instantiates a \ref Heap.
kpeter@244
   977
kpeter@244
   978
    ///This function instantiates a \ref Heap.
kpeter@244
   979
    /// \param r is the HeapCrossRef which is used.
kpeter@244
   980
    static Heap *createHeap(HeapCrossRef& r)
alpar@100
   981
    {
kpeter@244
   982
      return new Heap(r);
alpar@100
   983
    }
alpar@100
   984
kpeter@244
   985
    ///\brief The type of the map that stores the predecessor
alpar@100
   986
    ///arcs of the shortest paths.
alpar@209
   987
    ///
kpeter@244
   988
    ///The type of the map that stores the predecessor
alpar@100
   989
    ///arcs of the shortest paths.
alpar@100
   990
    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
kpeter@244
   991
    typedef NullMap <typename Digraph::Node,typename Digraph::Arc> PredMap;
kpeter@244
   992
    ///Instantiates a \ref PredMap.
alpar@209
   993
alpar@209
   994
    ///This function instantiates a \ref PredMap.
kpeter@244
   995
    ///\param g is the digraph, to which we would like to define the
kpeter@244
   996
    ///\ref PredMap.
kpeter@244
   997
    ///\todo The digraph alone may be insufficient to initialize
alpar@100
   998
#ifdef DOXYGEN
kpeter@244
   999
    static PredMap *createPredMap(const Digraph &g)
alpar@100
  1000
#else
kpeter@244
  1001
    static PredMap *createPredMap(const Digraph &)
alpar@100
  1002
#endif
alpar@100
  1003
    {
alpar@100
  1004
      return new PredMap();
alpar@100
  1005
    }
alpar@209
  1006
kpeter@244
  1007
    ///The type of the map that indicates which nodes are processed.
kpeter@244
  1008
kpeter@244
  1009
    ///The type of the map that indicates which nodes are processed.
alpar@100
  1010
    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
alpar@100
  1011
    ///By default it is a NullMap.
alpar@100
  1012
    ///\todo If it is set to a real map,
alpar@100
  1013
    ///Dijkstra::processed() should read this.
alpar@100
  1014
    ///\todo named parameter to set this type, function to read and write.
alpar@100
  1015
    typedef NullMap<typename Digraph::Node,bool> ProcessedMap;
kpeter@244
  1016
    ///Instantiates a \ref ProcessedMap.
alpar@209
  1017
alpar@209
  1018
    ///This function instantiates a \ref ProcessedMap.
alpar@100
  1019
    ///\param g is the digraph, to which
kpeter@244
  1020
    ///we would like to define the \ref ProcessedMap.
alpar@100
  1021
#ifdef DOXYGEN
kpeter@244
  1022
    static ProcessedMap *createProcessedMap(const Digraph &g)
alpar@100
  1023
#else
kpeter@244
  1024
    static ProcessedMap *createProcessedMap(const Digraph &)
alpar@100
  1025
#endif
alpar@100
  1026
    {
alpar@100
  1027
      return new ProcessedMap();
alpar@100
  1028
    }
alpar@209
  1029
kpeter@244
  1030
    ///The type of the map that stores the distances of the nodes.
kpeter@244
  1031
kpeter@244
  1032
    ///The type of the map that stores the distances of the nodes.
alpar@100
  1033
    ///It must meet the \ref concepts::WriteMap "WriteMap" concept.
kpeter@244
  1034
    typedef NullMap<typename Digraph::Node,Value> DistMap;
kpeter@244
  1035
    ///Instantiates a \ref DistMap.
alpar@209
  1036
alpar@209
  1037
    ///This function instantiates a \ref DistMap.
alpar@210
  1038
    ///\param g is the digraph, to which we would like to define
alpar@210
  1039
    ///the \ref DistMap
alpar@100
  1040
#ifdef DOXYGEN
kpeter@244
  1041
    static DistMap *createDistMap(const Digraph &g)
alpar@100
  1042
#else
kpeter@244
  1043
    static DistMap *createDistMap(const Digraph &)
alpar@100
  1044
#endif
alpar@100
  1045
    {
alpar@100
  1046
      return new DistMap();
alpar@100
  1047
    }
alpar@100
  1048
  };
alpar@209
  1049
kpeter@244
  1050
  /// Default traits class used by \ref DijkstraWizard
alpar@100
  1051
alpar@100
  1052
  /// To make it easier to use Dijkstra algorithm
kpeter@244
  1053
  /// we have created a wizard class.
alpar@100
  1054
  /// This \ref DijkstraWizard class needs default traits,
kpeter@244
  1055
  /// as well as the \ref Dijkstra class.
alpar@100
  1056
  /// The \ref DijkstraWizardBase is a class to be the default traits of the
alpar@100
  1057
  /// \ref DijkstraWizard class.
alpar@100
  1058
  /// \todo More named parameters are required...
alpar@100
  1059
  template<class GR,class LM>
alpar@100
  1060
  class DijkstraWizardBase : public DijkstraWizardDefaultTraits<GR,LM>
alpar@100
  1061
  {
alpar@100
  1062
    typedef DijkstraWizardDefaultTraits<GR,LM> Base;
alpar@100
  1063
  protected:
kpeter@244
  1064
    //The type of the nodes in the digraph.
alpar@100
  1065
    typedef typename Base::Digraph::Node Node;
alpar@100
  1066
kpeter@244
  1067
    //Pointer to the digraph the algorithm runs on.
alpar@100
  1068
    void *_g;
kpeter@244
  1069
    //Pointer to the length map
alpar@100
  1070
    void *_length;
kpeter@244
  1071
    //Pointer to the map of predecessors arcs.
alpar@100
  1072
    void *_pred;
kpeter@244
  1073
    //Pointer to the map of distances.
alpar@100
  1074
    void *_dist;
kpeter@244
  1075
    //Pointer to the source node.
alpar@100
  1076
    Node _source;
alpar@100
  1077
kpeter@244
  1078
  public:
alpar@100
  1079
    /// Constructor.
alpar@209
  1080
alpar@100
  1081
    /// This constructor does not require parameters, therefore it initiates
alpar@100
  1082
    /// all of the attributes to default values (0, INVALID).
alpar@100
  1083
    DijkstraWizardBase() : _g(0), _length(0), _pred(0),
alpar@209
  1084
                           _dist(0), _source(INVALID) {}
alpar@100
  1085
alpar@100
  1086
    /// Constructor.
alpar@209
  1087
alpar@100
  1088
    /// This constructor requires some parameters,
alpar@100
  1089
    /// listed in the parameters list.
alpar@100
  1090
    /// Others are initiated to 0.
kpeter@244
  1091
    /// \param g The digraph the algorithm runs on.
kpeter@244
  1092
    /// \param l The length map.
kpeter@244
  1093
    /// \param s The source node.
alpar@100
  1094
    DijkstraWizardBase(const GR &g,const LM &l, Node s=INVALID) :
alpar@209
  1095
      _g(reinterpret_cast<void*>(const_cast<GR*>(&g))),
alpar@209
  1096
      _length(reinterpret_cast<void*>(const_cast<LM*>(&l))),
alpar@100
  1097
      _pred(0), _dist(0), _source(s) {}
alpar@100
  1098
alpar@100
  1099
  };
alpar@209
  1100
kpeter@244
  1101
  /// Auxiliary class for the function type interface of Dijkstra algorithm.
alpar@100
  1102
kpeter@244
  1103
  /// This auxiliary class is created to implement the function type
kpeter@244
  1104
  /// interface of \ref Dijkstra algorithm. It uses the functions and features
kpeter@244
  1105
  /// of the plain \ref Dijkstra, but it is much simpler to use it.
kpeter@244
  1106
  /// It should only be used through the \ref dijkstra() function, which makes
kpeter@244
  1107
  /// it easier to use the algorithm.
alpar@100
  1108
  ///
alpar@100
  1109
  /// Simplicity means that the way to change the types defined
alpar@100
  1110
  /// in the traits class is based on functions that returns the new class
alpar@100
  1111
  /// and not on templatable built-in classes.
alpar@100
  1112
  /// When using the plain \ref Dijkstra
alpar@100
  1113
  /// the new class with the modified type comes from
alpar@100
  1114
  /// the original class by using the ::
alpar@100
  1115
  /// operator. In the case of \ref DijkstraWizard only
kpeter@244
  1116
  /// a function have to be called, and it will
alpar@100
  1117
  /// return the needed class.
alpar@100
  1118
  ///
kpeter@244
  1119
  /// It does not have own \ref run() method. When its \ref run() method
kpeter@244
  1120
  /// is called, it initiates a plain \ref Dijkstra object, and calls the
kpeter@244
  1121
  /// \ref Dijkstra::run() method of it.
alpar@100
  1122
  template<class TR>
alpar@100
  1123
  class DijkstraWizard : public TR
alpar@100
  1124
  {
alpar@100
  1125
    typedef TR Base;
alpar@100
  1126
kpeter@244
  1127
    ///The type of the digraph the algorithm runs on.
alpar@100
  1128
    typedef typename TR::Digraph Digraph;
kpeter@244
  1129
alpar@100
  1130
    typedef typename Digraph::Node Node;
alpar@100
  1131
    typedef typename Digraph::NodeIt NodeIt;
alpar@100
  1132
    typedef typename Digraph::Arc Arc;
alpar@100
  1133
    typedef typename Digraph::OutArcIt OutArcIt;
alpar@209
  1134
alpar@100
  1135
    ///The type of the map that stores the arc lengths.
alpar@100
  1136
    typedef typename TR::LengthMap LengthMap;
alpar@100
  1137
    ///The type of the length of the arcs.
alpar@100
  1138
    typedef typename LengthMap::Value Value;
kpeter@244
  1139
    ///\brief The type of the map that stores the predecessor
alpar@100
  1140
    ///arcs of the shortest paths.
alpar@100
  1141
    typedef typename TR::PredMap PredMap;
kpeter@244
  1142
    ///The type of the map that stores the distances of the nodes.
alpar@100
  1143
    typedef typename TR::DistMap DistMap;
kpeter@244
  1144
    ///The type of the map that indicates which nodes are processed.
kpeter@244
  1145
    typedef typename TR::ProcessedMap ProcessedMap;
alpar@100
  1146
    ///The heap type used by the dijkstra algorithm.
alpar@100
  1147
    typedef typename TR::Heap Heap;
kpeter@244
  1148
alpar@100
  1149
  public:
kpeter@244
  1150
alpar@100
  1151
    /// Constructor.
alpar@100
  1152
    DijkstraWizard() : TR() {}
alpar@100
  1153
alpar@100
  1154
    /// Constructor that requires parameters.
alpar@100
  1155
alpar@100
  1156
    /// Constructor that requires parameters.
alpar@100
  1157
    /// These parameters will be the default values for the traits class.
alpar@100
  1158
    DijkstraWizard(const Digraph &g,const LengthMap &l, Node s=INVALID) :
alpar@100
  1159
      TR(g,l,s) {}
alpar@100
  1160
alpar@100
  1161
    ///Copy constructor
alpar@100
  1162
    DijkstraWizard(const TR &b) : TR(b) {}
alpar@100
  1163
alpar@100
  1164
    ~DijkstraWizard() {}
alpar@100
  1165
kpeter@244
  1166
    ///Runs Dijkstra algorithm from a source node.
alpar@209
  1167
kpeter@244
  1168
    ///Runs Dijkstra algorithm from a source node.
kpeter@244
  1169
    ///The node can be given with the \ref source() function.
alpar@100
  1170
    void run()
alpar@100
  1171
    {
alpar@100
  1172
      if(Base::_source==INVALID) throw UninitializedParameter();
alpar@209
  1173
      Dijkstra<Digraph,LengthMap,TR>
alpar@209
  1174
        dij(*reinterpret_cast<const Digraph*>(Base::_g),
alpar@100
  1175
            *reinterpret_cast<const LengthMap*>(Base::_length));
alpar@100
  1176
      if(Base::_pred) dij.predMap(*reinterpret_cast<PredMap*>(Base::_pred));
alpar@100
  1177
      if(Base::_dist) dij.distMap(*reinterpret_cast<DistMap*>(Base::_dist));
alpar@100
  1178
      dij.run(Base::_source);
alpar@100
  1179
    }
alpar@100
  1180
alpar@100
  1181
    ///Runs Dijkstra algorithm from the given node.
alpar@100
  1182
alpar@100
  1183
    ///Runs Dijkstra algorithm from the given node.
alpar@100
  1184
    ///\param s is the given source.
alpar@100
  1185
    void run(Node s)
alpar@100
  1186
    {
alpar@100
  1187
      Base::_source=s;
alpar@100
  1188
      run();
alpar@100
  1189
    }
alpar@100
  1190
kpeter@244
  1191
    /// Sets the source node, from which the Dijkstra algorithm runs.
kpeter@244
  1192
kpeter@244
  1193
    /// Sets the source node, from which the Dijkstra algorithm runs.
kpeter@244
  1194
    /// \param s is the source node.
kpeter@244
  1195
    DijkstraWizard<TR> &source(Node s)
kpeter@244
  1196
    {
kpeter@244
  1197
      Base::_source=s;
kpeter@244
  1198
      return *this;
kpeter@244
  1199
    }
kpeter@244
  1200
alpar@100
  1201
    template<class T>
alpar@100
  1202
    struct DefPredMapBase : public Base {
alpar@100
  1203
      typedef T PredMap;
alpar@100
  1204
      static PredMap *createPredMap(const Digraph &) { return 0; };
alpar@100
  1205
      DefPredMapBase(const TR &b) : TR(b) {}
alpar@100
  1206
    };
alpar@100
  1207
    ///\brief \ref named-templ-param "Named parameter"
kpeter@244
  1208
    ///for setting \ref PredMap object.
alpar@100
  1209
    ///
kpeter@244
  1210
    ///\ref named-templ-param "Named parameter"
kpeter@244
  1211
    ///for setting \ref PredMap object.
alpar@100
  1212
    template<class T>
alpar@209
  1213
    DijkstraWizard<DefPredMapBase<T> > predMap(const T &t)
alpar@100
  1214
    {
alpar@100
  1215
      Base::_pred=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100
  1216
      return DijkstraWizard<DefPredMapBase<T> >(*this);
alpar@100
  1217
    }
alpar@209
  1218
alpar@100
  1219
    template<class T>
kpeter@244
  1220
    struct DefProcessedMapBase : public Base {
kpeter@244
  1221
      typedef T ProcessedMap;
kpeter@244
  1222
      static ProcessedMap *createProcessedMap(const Digraph &) { return 0; };
kpeter@244
  1223
      DefProcessedMapBase(const TR &b) : TR(b) {}
kpeter@244
  1224
    };
kpeter@244
  1225
    ///\brief \ref named-templ-param "Named parameter"
kpeter@244
  1226
    ///for setting \ref ProcessedMap object.
kpeter@244
  1227
    ///
kpeter@244
  1228
    /// \ref named-templ-param "Named parameter"
kpeter@244
  1229
    ///for setting \ref ProcessedMap object.
kpeter@244
  1230
    template<class T>
kpeter@244
  1231
    DijkstraWizard<DefProcessedMapBase<T> > processedMap(const T &t)
kpeter@244
  1232
    {
kpeter@244
  1233
      Base::_processed=reinterpret_cast<void*>(const_cast<T*>(&t));
kpeter@244
  1234
      return DijkstraWizard<DefProcessedMapBase<T> >(*this);
kpeter@244
  1235
    }
kpeter@244
  1236
kpeter@244
  1237
    template<class T>
alpar@100
  1238
    struct DefDistMapBase : public Base {
alpar@100
  1239
      typedef T DistMap;
alpar@100
  1240
      static DistMap *createDistMap(const Digraph &) { return 0; };
alpar@100
  1241
      DefDistMapBase(const TR &b) : TR(b) {}
alpar@100
  1242
    };
alpar@100
  1243
    ///\brief \ref named-templ-param "Named parameter"
kpeter@244
  1244
    ///for setting \ref DistMap object.
alpar@100
  1245
    ///
kpeter@244
  1246
    ///\ref named-templ-param "Named parameter"
kpeter@244
  1247
    ///for setting \ref DistMap object.
alpar@100
  1248
    template<class T>
alpar@209
  1249
    DijkstraWizard<DefDistMapBase<T> > distMap(const T &t)
alpar@100
  1250
    {
alpar@100
  1251
      Base::_dist=reinterpret_cast<void*>(const_cast<T*>(&t));
alpar@100
  1252
      return DijkstraWizard<DefDistMapBase<T> >(*this);
alpar@100
  1253
    }
alpar@209
  1254
alpar@100
  1255
  };
alpar@209
  1256
alpar@100
  1257
  ///Function type interface for Dijkstra algorithm.
alpar@100
  1258
alpar@100
  1259
  /// \ingroup shortest_path
alpar@100
  1260
  ///Function type interface for Dijkstra algorithm.
alpar@100
  1261
  ///
alpar@100
  1262
  ///This function also has several
alpar@100
  1263
  ///\ref named-templ-func-param "named parameters",
alpar@100
  1264
  ///they are declared as the members of class \ref DijkstraWizard.
alpar@100
  1265
  ///The following
alpar@100
  1266
  ///example shows how to use these parameters.
alpar@100
  1267
  ///\code
alpar@100
  1268
  ///  dijkstra(g,length,source).predMap(preds).run();
alpar@100
  1269
  ///\endcode
alpar@100
  1270
  ///\warning Don't forget to put the \ref DijkstraWizard::run() "run()"
alpar@100
  1271
  ///to the end of the parameter list.
alpar@100
  1272
  ///\sa DijkstraWizard
alpar@100
  1273
  ///\sa Dijkstra
alpar@100
  1274
  template<class GR, class LM>
alpar@100
  1275
  DijkstraWizard<DijkstraWizardBase<GR,LM> >
alpar@100
  1276
  dijkstra(const GR &g,const LM &l,typename GR::Node s=INVALID)
alpar@100
  1277
  {
alpar@100
  1278
    return DijkstraWizard<DijkstraWizardBase<GR,LM> >(g,l,s);
alpar@100
  1279
  }
alpar@100
  1280
alpar@100
  1281
} //END OF NAMESPACE LEMON
alpar@100
  1282
alpar@100
  1283
#endif