/* -*- mode: C++; indent-tabs-mode: nil; -*-

 /* -*- mode: C++; indent-tabs-mode: nil; -*-

  *

  *

  * This file is a part of LEMON, a generic C++ optimization library.

  * This file is a part of LEMON, a generic C++ optimization library.

  *

  *

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  *

  * Permission to use, modify and distribute this software is granted

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * provided that this copyright notice appears in all copies. For

     ///

     ///

     ///\note The moved arcs are joined to node \c u using changeSource()

     ///\note The moved arcs are joined to node \c u using changeSource()

     ///or changeTarget(), thus \c ArcIt and \c OutArcIt iterators are

     ///or changeTarget(), thus \c ArcIt and \c OutArcIt iterators are

     ///invalidated for the outgoing arcs of node \c v and \c InArcIt

     ///invalidated for the outgoing arcs of node \c v and \c InArcIt

     ///iterators are invalidated for the incomming arcs of \c v.

     ///iterators are invalidated for the incomming arcs of \c v.

     ///loops are also invalidated. Other iterators remain valid.

     ///loops are also invalidated. Other iterators remain valid.

     ///

     ///

     ///\warning This functionality cannot be used together with the Snapshot

     ///\warning This functionality cannot be used together with the Snapshot

     ///feature.

     ///feature.

     void contract(Node u, Node v, bool r = true)

     void contract(Node u, Node v, bool r = true)

     /// Class to make a snapshot of the digraph and restore it later.

     /// Class to make a snapshot of the digraph and restore it later.

     ///

     ///

     /// The newly added nodes and arcs can be removed using the

     /// The newly added nodes and arcs can be removed using the

     /// restore() function.

     /// restore() function.

     ///

     ///

     /// i.e. you cannot add the removed nodes and arcs again using

     /// i.e. you cannot add the removed nodes and arcs again using

     /// another Snapshot instance.

     /// another Snapshot instance.

     ///

     ///

     /// \warning Node and arc deletions and other modifications (e.g.

     /// \warning Node and arc deletions and other modifications (e.g.

     /// reversing, contracting, splitting arcs or nodes) cannot be

     /// reversing, contracting, splitting arcs or nodes) cannot be

     /// then the newly created loops are removed.

     /// then the newly created loops are removed.

     ///

     ///

     /// \note The moved edges are joined to node \c a using changeU()

     /// \note The moved edges are joined to node \c a using changeU()

     /// or changeV(), thus all edge and arc iterators whose base node is

     /// or changeV(), thus all edge and arc iterators whose base node is

     /// \c b are invalidated.

     /// \c b are invalidated.

     /// loops are also invalidated. Other iterators remain valid.

     /// loops are also invalidated. Other iterators remain valid.

     ///

     ///

     ///\warning This functionality cannot be used together with the

     ///\warning This functionality cannot be used together with the

     ///Snapshot feature.

     ///Snapshot feature.

     void contract(Node a, Node b, bool r = true) {

     void contract(Node a, Node b, bool r = true) {

     /// Class to make a snapshot of the graph and restore it later.

     /// Class to make a snapshot of the graph and restore it later.

     ///

     ///

     /// The newly added nodes and edges can be removed

     /// The newly added nodes and edges can be removed

     /// using the restore() function.

     /// using the restore() function.

     ///

     ///

     /// i.e. you cannot add the removed nodes and edges again using

     /// i.e. you cannot add the removed nodes and edges again using

     /// another Snapshot instance.

     /// another Snapshot instance.

     ///

     ///

     /// \warning Node and edge deletions and other modifications

     /// \warning Node and edge deletions and other modifications

     /// (e.g. changing the end-nodes of edges or contracting nodes)

     /// (e.g. changing the end-nodes of edges or contracting nodes)