diff -r d8475431bbbb -r 8e85e6bbefdf lemon/unionfind.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lemon/unionfind.h	Mon May 23 04:48:14 2005 +0000
@@ -0,0 +1,724 @@
+/* -*- C++ -*-
+ * lemon/unionfind.h - Part of LEMON, a generic C++ optimization library
+ *
+ * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
+ * (Egervary Research Group on Combinatorial Optimization, EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+#ifndef LEMON_UNION_FIND_H
+#define LEMON_UNION_FIND_H
+
+//!\ingroup auxdat
+//!\file
+//!\brief Union-Find data structures.
+//!
+//!\bug unionfind_test.cc doesn't work with Intel compiler. It compiles but
+//!fails to run (Segmentation fault).
+
+
+#include <vector>
+#include <list>
+#include <utility>
+#include <algorithm>
+
+#include <lemon/invalid.h>
+
+namespace lemon {
+
+  //! \addtogroup auxdat
+  //! @{
+
+  /**
+   * \brief A \e Union-Find data structure implementation
+   *
+   * The class implements the \e Union-Find data structure. 
+   * The union operation uses rank heuristic, while
+   * the find operation uses path compression.
+   * This is a very simple but efficient implementation, providing 
+   * only four methods: join (union), find, insert and size.
+   * For more features see the \ref UnionFindEnum class.
+   *
+   * It is primarily used in Kruskal algorithm for finding minimal
+   * cost spanning tree in a graph.
+   * \sa kruskal()
+   *
+   * \pre The elements are automatically added only if the map 
+   * given to the constructor was filled with -1's. Otherwise you
+   * need to add all the elements by the \ref insert() method.
+   * \bug It is not clear what the constructor parameter is used for.
+   */
+
+  template <typename T, typename TIntMap>
+  class UnionFind {
+    
+  public:
+    typedef T ElementType;
+    typedef std::pair<int,int> PairType;
+
+  private:
+    std::vector<PairType> data;
+    TIntMap& map;
+
+  public:
+    UnionFind(TIntMap& m) : map(m) {}
+
+    /**
+     * \brief Returns the index of the element's component.
+     *
+     * The method returns the index of the element's component.
+     * This is an integer between zero and the number of inserted elements.
+     */
+
+    int find(T a)
+    {
+      int comp0 = map[a];
+      if (comp0 < 0) {
+	return insert(a);
+      }
+      int comp = comp0;
+      int next;
+      while ( (next = data[comp].first) != comp) {
+	comp = next;
+      }
+      while ( (next = data[comp0].first) != comp) {
+	data[comp0].first = comp;
+	comp0 = next;
+      }
+
+      return comp;
+    }
+
+    /**
+     * \brief Inserts a new element into the structure.
+     *
+     * This method inserts a new element into the data structure. 
+     *
+     * It is not required to use this method:
+     * if the map given to the constructor was filled 
+     * with -1's then it is called automatically
+     * on the first \ref find or \ref join.
+     *
+     * The method returns the index of the new component.
+     */
+
+    int insert(T a)
+    {
+      int n = data.size();
+      data.push_back(std::make_pair(n, 1));
+      map.set(a,n);
+      return n;
+    }
+
+    /**
+     * \brief Joining the components of element \e a and element \e b.
+     *
+     * This is the \e union operation of the Union-Find structure. 
+     * Joins the component of element \e a and component of
+     * element \e b. If \e a and \e b are in the same component then
+     * it returns false otherwise it returns true.
+     */
+
+    bool join(T a, T b)
+    {
+      int ca = find(a);
+      int cb = find(b);
+
+      if ( ca == cb ) 
+	return false;
+
+      if ( data[ca].second > data[cb].second ) {
+	data[cb].first = ca;
+	data[ca].second += data[cb].second;
+      }
+      else {
+	data[ca].first = cb;
+	data[cb].second += data[ca].second;
+      }
+      return true;
+    }
+
+    /**
+     * \brief Returns the size of the component of element \e a.
+     *
+     * Returns the size of the component of element \e a.
+     */
+
+    int size(T a)
+    {
+      int ca = find(a);
+      return data[ca].second;
+    }
+
+  };
+
+
+
+
+  /*******************************************************/
+
+
+#ifdef DEVELOPMENT_DOCS
+
+  /**
+   * \brief The auxiliary class for the \ref UnionFindEnum class.
+   *
+   * In the \ref UnionFindEnum class all components are represented as
+   * a std::list. 
+   * Items of these lists are UnionFindEnumItem structures.
+   *
+   * The class has four fields:
+   *  - T me - the actual element 
+   *  - IIter parent - the parent of the element in the union-find structure
+   *  - int size - the size of the component of the element. 
+   *            Only valid if the element
+   *            is the leader of the component.
+   *  - CIter my_class - pointer into the list of components 
+   *            pointing to the component of the element.
+   *            Only valid if the element is the leader of the component.
+   */
+
+#endif
+
+  template <typename T>
+  struct UnionFindEnumItem {
+
+    typedef std::list<UnionFindEnumItem> ItemList;
+    typedef std::list<ItemList> ClassList;
+    typedef typename ItemList::iterator IIter;
+    typedef typename ClassList::iterator CIter;
+
+    T me;
+    IIter parent;
+    int size;
+    CIter my_class;
+
+    UnionFindEnumItem() {}
+    UnionFindEnumItem(const T &_me, CIter _my_class): 
+      me(_me), size(1), my_class(_my_class) {}
+  };
+
+
+  /**
+   * \brief A \e Union-Find data structure implementation which
+   * is able to enumerate the components.
+   *
+   * The class implements a \e Union-Find data structure
+   * which is able to enumerate the components and the items in
+   * a component. If you don't need this feature then perhaps it's
+   * better to use the \ref UnionFind class which is more efficient.
+   *
+   * The union operation uses rank heuristic, while
+   * the find operation uses path compression.
+   *
+   * \pre You
+   * need to add all the elements by the \ref insert() method.
+   */
+
+
+  template <typename T, template <typename Item> class Map>
+  class UnionFindEnum {
+
+    typedef std::list<UnionFindEnumItem<T> > ItemList;
+    typedef std::list<ItemList> ClassList;
+    typedef typename ItemList::iterator IIter;
+    typedef typename ItemList::const_iterator IcIter;
+    typedef typename ClassList::iterator CIter;
+    typedef typename ClassList::const_iterator CcIter;
+
+  public:
+    typedef T ElementType;
+    typedef UnionFindEnumItem<T> ItemType;
+    typedef Map< IIter > MapType;
+
+  private:
+    MapType& m;
+    ClassList classes;
+
+    IIter _find(IIter a) const {
+      IIter comp = a;
+      IIter next;
+      while( (next = comp->parent) != comp ) {
+	comp = next;
+      }
+
+      IIter comp1 = a;
+      while( (next = comp1->parent) != comp ) {
+	comp1->parent = comp->parent;
+	comp1 = next;
+      }
+      return comp;
+    }
+
+  public:
+    UnionFindEnum(MapType& _m) : m(_m) {}
+
+
+    /**
+     * \brief Inserts the given element into a new component.
+     *
+     * This method creates a new component consisting only of the
+     * given element.
+     */
+
+    void insert(const T &a)
+    {
+
+
+      classes.push_back(ItemList());
+      CIter aclass = classes.end();
+      --aclass;
+
+      ItemList &alist = *aclass;
+      alist.push_back(ItemType(a, aclass));
+      IIter ai = alist.begin();
+
+      ai->parent = ai;
+      m.set(a, ai);
+
+    }
+
+    /**
+     * \brief Inserts the given element into the component of the others.
+     *
+     * This methods inserts the element \e a into the component of the
+     * element \e comp. 
+     */
+
+    void insert(const T &a, const T &comp) {
+      
+      IIter clit = _find(m[comp]);
+      ItemList &c = *clit->my_class;
+      c.push_back(ItemType(a,0));
+      IIter ai = c.end();
+      --ai;
+      ai->parent = clit;
+      m.set(a, ai);
+      ++clit->size;
+    }
+
+
+    /**
+     * \brief Finds the leader of the component of the given element.
+     *
+     * The method returns the leader of the component of the given element.
+     */
+
+    T find(const T &a) const {
+      return _find(m[a])->me;
+    }
+
+
+    /**
+     * \brief Joining the component of element \e a and element \e b.
+     *
+     * This is the \e union operation of the Union-Find structure. 
+     * Joins the component of element \e a and component of
+     * element \e b. If \e a and \e b are in the same component then
+     * returns false else returns true.
+     */
+
+    bool join(T a, T b) {
+
+      IIter ca = _find(m[a]);
+      IIter cb = _find(m[b]);
+
+      if ( ca == cb ) {
+	return false;
+      }
+
+      if ( ca->size > cb->size ) {
+
+	cb->parent = ca->parent;
+	ca->size += cb->size;
+	
+	ItemList &alist = *ca->my_class;
+	alist.splice(alist.end(),*cb->my_class);
+
+	classes.erase(cb->my_class);
+	cb->my_class = 0;
+      }
+      else {
+
+	ca->parent = cb->parent;
+	cb->size += ca->size;
+	
+	ItemList &blist = *cb->my_class;
+	blist.splice(blist.end(),*ca->my_class);
+
+	classes.erase(ca->my_class);
+	ca->my_class = 0;
+      }
+
+      return true;
+    }
+
+
+    /**
+     * \brief Returns the size of the component of element \e a.
+     *
+     * Returns the size of the component of element \e a.
+     */
+
+    int size(const T &a) const {
+      return _find(m[a])->size;
+    }
+
+
+    /**
+     * \brief Splits up the component of the element. 
+     *
+     * Splitting the component of the element into sigleton
+     * components (component of size one).
+     */
+
+    void split(const T &a) {
+
+      IIter ca = _find(m[a]);
+ 
+      if ( ca->size == 1 )
+	return;
+      
+      CIter aclass = ca->my_class;
+
+      for(IIter curr = ca; ++curr != aclass->end(); curr=ca) {
+	classes.push_back(ItemList());
+	CIter nl = --classes.end();
+	nl->splice(nl->end(), *aclass, curr);
+
+	curr->size=1;
+	curr->parent=curr;
+	curr->my_class = nl;
+      }
+
+      ca->size=1;
+      return;
+    }
+
+
+    /**
+     * \brief Sets the given element to the leader element of its component.
+     *
+     * Sets the given element to the leader element of its component.
+     */
+
+    void makeRep(const T &a) {
+
+      IIter ia = m[a];
+      IIter la = _find(ia);
+      if (la == ia) return;
+
+      ia->my_class = la->my_class;
+      la->my_class = 0;
+
+      ia->size = la->size;
+
+      CIter l = ia->my_class;
+      l->splice(l->begin(),*l,ia);
+
+      ia->parent = ia;
+      la->parent = ia;
+    }
+
+    /**
+     * \brief Moves the given element to an other component.
+     *
+     * This method moves the element \e a from its component
+     * to the component of \e comp.
+     * If \e a and \e comp are in the same component then
+     * it returns false otherwise it returns true.
+     */
+
+    bool move(const T &a, const T &comp) {
+
+      IIter ai = m[a];
+      IIter lai = _find(ai);
+      IIter clit = _find(m[comp]);
+
+      if (lai == clit)
+	return false;
+
+      ItemList &cl = *clit->my_class,
+	&al = *lai->my_class;
+
+      bool is_leader = (lai == ai);
+      bool singleton = false;
+
+      if (is_leader) {
+	++lai;
+      }
+
+      cl.splice(cl.end(), al, ai);
+
+      if (is_leader) {
+	if (ai->size == 1) {
+	  classes.erase(ai->my_class);
+	  singleton = true;
+	}
+	else {
+	  lai->size = ai->size; 
+	  lai->my_class = ai->my_class;	
+	}
+      }
+      if (!singleton) {
+	for (IIter i = lai; i != al.end(); ++i)
+	  i->parent = lai;
+	--lai->size;
+      }
+
+      ai->parent = clit;
+      ai->my_class = 0;
+      ++clit->size;
+
+      return true;
+    }
+
+
+    /**
+     * \brief Removes the given element from the structure.
+     *
+     * Removes the given element from the structure.
+     *
+     * Removes the element from its component and if the component becomes
+     * empty then removes that component from the component list.
+     */
+    void erase(const T &a) {
+
+      IIter ma = m[a];
+      if (ma == 0) return;
+
+      IIter la = _find(ma);
+      if (la == ma) {
+	if (ma -> size == 1){
+	  classes.erase(ma->my_class);
+	  m.set(a,0);
+	  return;
+	}
+	++la;
+	la->size = ma->size; 
+	la->my_class = ma->my_class;	
+      }
+
+      for (IIter i = la; i != la->my_class->end(); ++i) {
+	i->parent = la;
+      }
+
+      la->size--;
+      la->my_class->erase(ma);
+      m.set(a,0);
+    }
+
+    /**
+     * \brief Removes the component of the given element from the structure.
+     *
+     * Removes the component of the given element from the structure.
+     */
+
+    void eraseClass(const T &a) {
+      IIter ma = m[a];
+      if (ma == 0) return;
+#     ifdef DEBUG
+      CIter c = _find(ma)->my_class;
+      for (IIter i=c->begin(); i!=c->end(); ++i)
+	m.set(i->me, 0);
+#     endif
+      classes.erase(_find(ma)->my_class);
+    }
+
+
+    class ClassIt {
+      friend class UnionFindEnum;
+
+      CcIter i;
+    public:
+      ClassIt(Invalid): i(0) {}
+      ClassIt() {}
+      
+      operator const T& () const { 
+	ItemList const &ll = *i;
+	return (ll.begin())->me; }
+      bool operator == (ClassIt it) const {
+	return (i == it.i);
+      }
+      bool operator != (ClassIt it) const {
+	return (i != it.i);
+      }
+      bool operator < (ClassIt it) const {
+	return (i < it.i);
+      }
+
+      bool valid() const { return i != 0; }
+    private:
+      void first(const ClassList &l) { i = l.begin(); validate(l); }
+      void next(const ClassList &l) {
+	++i; 
+	validate(l);
+      }
+      void validate(const ClassList &l) {
+	if ( i == l.end() ) 
+	  i = 0;
+      }
+    };
+
+    /**
+     * \brief Sets the iterator to point to the first component.
+     * 
+     * Sets the iterator to point to the first component.
+     *
+     * With the \ref first, \ref valid and \ref next methods you can
+     * iterate through the components. For example:
+     * \code
+     * UnionFindEnum<Graph::Node, Graph::NodeMap>::MapType map(G);
+     * UnionFindEnum<Graph::Node, Graph::NodeMap> U(map);
+     * UnionFindEnum<Graph::Node, Graph::NodeMap>::ClassIt iter;
+     *  for (U.first(iter); U.valid(iter); U.next(iter)) {
+     *    // iter is convertible to Graph::Node
+     *    cout << iter << endl;
+     *  }
+     * \endcode
+     */
+
+    ClassIt& first(ClassIt& it) const {
+      it.first(classes);
+      return it;
+    }
+
+    /**
+     * \brief Returns whether the iterator is valid.
+     *
+     * Returns whether the iterator is valid.
+     *
+     * With the \ref first, \ref valid and \ref next methods you can
+     * iterate through the components. See the example here: \ref first.
+     */
+
+    bool valid(ClassIt const &it) const {
+      return it.valid(); 
+    }
+
+    /**
+     * \brief Steps the iterator to the next component. 
+     *
+     * Steps the iterator to the next component.
+     *
+     * With the \ref first, \ref valid and \ref next methods you can
+     * iterate through the components. See the example here: \ref first.
+     */
+
+    ClassIt& next(ClassIt& it) const {
+      it.next(classes);
+      return it;
+    }
+
+
+    class ItemIt {
+      friend class UnionFindEnum;
+
+      IcIter i;
+      const ItemList *l;
+    public:
+      ItemIt(Invalid): i(0) {}
+      ItemIt() {}
+      
+      operator const T& () const { return i->me; }
+      bool operator == (ItemIt it) const {
+	return (i == it.i);
+      }
+      bool operator != (ItemIt it) const {
+	return (i != it.i);
+      }
+      bool operator < (ItemIt it) const {
+	return (i < it.i);
+      }
+
+      bool valid() const { return i != 0; }
+    private:
+      void first(const ItemList &il) { l=&il; i = l->begin(); validate(); }
+      void next() {
+	++i; 
+	validate();
+      }
+      void validate() {
+	if ( i == l->end() ) 
+	  i = 0;
+      }
+    };
+
+
+
+    /**
+     * \brief Sets the iterator to point to the first element of the component.
+     * 
+     * \anchor first2 
+     * Sets the iterator to point to the first element of the component.
+     *
+     * With the \ref first2 "first", \ref valid2 "valid" 
+     * and \ref next2 "next" methods you can
+     * iterate through the elements of a component. For example
+     * (iterating through the component of the node \e node):
+     * \code
+     * Graph::Node node = ...;
+     * UnionFindEnum<Graph::Node, Graph::NodeMap>::MapType map(G);
+     * UnionFindEnum<Graph::Node, Graph::NodeMap> U(map);
+     * UnionFindEnum<Graph::Node, Graph::NodeMap>::ItemIt iiter;
+     *   for (U.first(iiter, node); U.valid(iiter); U.next(iiter)) {
+     *     // iiter is convertible to Graph::Node
+     *     cout << iiter << endl;
+     *   }
+     * \endcode
+     */
+    
+    ItemIt& first(ItemIt& it, const T& a) const {
+      it.first( * _find(m[a])->my_class );
+      return it;
+    }
+
+    /**
+     * \brief Returns whether the iterator is valid.
+     *
+     * \anchor valid2
+     * Returns whether the iterator is valid.
+     *
+     * With the \ref first2 "first", \ref valid2 "valid" 
+     * and \ref next2 "next" methods you can
+     * iterate through the elements of a component.
+     * See the example here: \ref first2 "first".
+     */
+
+    bool valid(ItemIt const &it) const {
+      return it.valid(); 
+    }
+
+    /**
+     * \brief Steps the iterator to the next component. 
+     *
+     * \anchor next2
+     * Steps the iterator to the next component.
+     *
+     * With the \ref first2 "first", \ref valid2 "valid" 
+     * and \ref next2 "next" methods you can
+     * iterate through the elements of a component.
+     * See the example here: \ref first2 "first".
+     */
+
+    ItemIt& next(ItemIt& it) const {
+      it.next();
+      return it;
+    }
+    
+  };
+
+
+  //! @}
+
+} //namespace lemon
+
+#endif //LEMON_UNION_FIND_H