src/work/johanna/unionfind.h
changeset 396 639c9daed784
parent 349 42c660f58702
child 462 0ab31578af67
equal deleted inserted replaced
2:a361efe2190f 3:bcbd2365ccca
     1 // -*- c++ -*- //
     1 // -*- c++ -*- //
     2 #ifndef HUGO_UNION_FIND_H
     2 #ifndef HUGO_UNION_FIND_H
     3 #define HUGO_UNION_FIND_H
     3 #define HUGO_UNION_FIND_H
     4 
     4 
     5 #include <vector>
     5 #include <vector>
       
     6 #include <list>
     6 #include <utility>
     7 #include <utility>
       
     8 #include <algorithm>
       
     9 
       
    10 #include <invalid.h>
     7 
    11 
     8 namespace hugo {
    12 namespace hugo {
     9 
    13 
    10   template <typename T, typename TIntMap>
    14   template <typename T, typename TIntMap>
    11   class UnionFind {
    15   class UnionFind {
    20 
    24 
    21   public:
    25   public:
    22     UnionFind(TIntMap& m) : map(m) {}
    26     UnionFind(TIntMap& m) : map(m) {}
    23 
    27 
    24 
    28 
    25     int whichComponent(T a)
    29     int find(T a)
    26     {
    30     {
    27       int comp0 = map[a];
    31       int comp0 = map[a];
    28       if (comp0 < 0) {
    32       if (comp0 < 0) {
    29 	return insertNewElement(a);
    33 	return insert(a);
    30       }
    34       }
    31       int comp = comp0;
    35       int comp = comp0;
    32       int next;
    36       int next;
    33       while ( (next = data[comp].first) != comp) {
    37       while ( (next = data[comp].first) != comp) {
    34 	comp = next;
    38 	comp = next;
    39       }
    43       }
    40 
    44 
    41       return comp;
    45       return comp;
    42     }
    46     }
    43 
    47 
    44     int insertNewElement(T a)
    48     int insert(T a)
    45     {
    49     {
    46       int n = data.size();
    50       int n = data.size();
    47       data.push_back(make_pair(n, 1));
    51       data.push_back(std::make_pair(n, 1));
    48       map.set(a,n);
    52       map.set(a,n);
    49       return n;
    53       return n;
    50     }
    54     }
    51 
    55 
    52     bool joinComponents(T a, T b)
    56     bool join(T a, T b)
    53     {
    57     {
    54       int ca = whichComponent(a);
    58       int ca = find(a);
    55       int cb = whichComponent(b);
    59       int cb = find(b);
    56 
    60 
    57       if ( ca == cb ) 
    61       if ( ca == cb ) 
    58 	return false;
    62 	return false;
    59 
    63 
    60       if ( data[ca].second > data[cb].second ) {
    64       if ( data[ca].second > data[cb].second ) {
    66 	data[cb].second += data[ca].second;
    70 	data[cb].second += data[ca].second;
    67       }
    71       }
    68       return true;
    72       return true;
    69     }
    73     }
    70 
    74 
    71     int componentSize(T a)
    75     int size(T a)
    72     {
    76     {
    73       int ca = whichComponent(a);
    77       int ca = find(a);
    74       return data[ca].second;
    78       return data[ca].second;
    75     }
    79     }
    76 
    80 
    77   };
    81   };
    78 
    82 
       
    83 
       
    84 
       
    85 
       
    86   /*******************************************************/
       
    87 
       
    88 
       
    89 
       
    90   template <typename T>
       
    91   struct UnionFindEnumItem {
       
    92 
       
    93     typedef std::list<UnionFindEnumItem> ItemList;
       
    94     typedef std::list<ItemList> ClassList;
       
    95     typedef typename ItemList::iterator IIter;
       
    96     typedef typename ClassList::iterator CIter;
       
    97 
       
    98     T me;
       
    99     IIter parent;
       
   100     int size;
       
   101     CIter my_class;
       
   102 
       
   103     UnionFindEnumItem() {}
       
   104     UnionFindEnumItem(const T &_me, CIter _my_class): 
       
   105       me(_me), size(1), my_class(_my_class) {}
       
   106   };
       
   107 
       
   108   template <typename T, template <typename Item> class Map>
       
   109   class UnionFindEnum {
       
   110 
       
   111     typedef std::list<UnionFindEnumItem<T> > ItemList;
       
   112     typedef std::list<ItemList> ClassList;
       
   113     typedef typename ItemList::iterator IIter;
       
   114     typedef typename ItemList::const_iterator IcIter;
       
   115     typedef typename ClassList::iterator CIter;
       
   116     typedef typename ClassList::const_iterator CcIter;
       
   117 
       
   118   public:
       
   119     typedef T ElementType;
       
   120     typedef UnionFindEnumItem<T> ItemType;
       
   121     typedef Map< IIter > MapType;
       
   122 
       
   123   private:
       
   124     MapType& m;
       
   125     ClassList classes;
       
   126 
       
   127     //    IIter where(const T &a) { return m[a]; }
       
   128     //    IIter parent(IIter a) { return a->parent; }
       
   129     //    P sibling(P a) { return &m[a->sibling]; }
       
   130 
       
   131     IIter _find(IIter a) const {
       
   132       IIter comp = a;
       
   133       IIter next;
       
   134       while( (next = comp->parent) != comp ) {
       
   135 	comp = next;
       
   136       }
       
   137 
       
   138       IIter comp1 = a;
       
   139       while( (next = comp1->parent) != comp ) {
       
   140 	comp1->parent = comp->parent;
       
   141 	comp1 = next;
       
   142       }
       
   143       return comp;
       
   144     }
       
   145 
       
   146   public:
       
   147     UnionFindEnum(MapType& _m) : m(_m) {}
       
   148 
       
   149     void insert(const T &a)
       
   150     {
       
   151 
       
   152 
       
   153       classes.push_back(ItemList());
       
   154       CIter aclass = classes.end();
       
   155       --aclass;
       
   156 
       
   157       ItemList &alist = *aclass;
       
   158       alist.push_back(ItemType(a, aclass));
       
   159       IIter ai = alist.begin();
       
   160 
       
   161       ai->parent = ai;
       
   162       m.set(a, ai);
       
   163 
       
   164     }
       
   165 
       
   166     T find(const T &a) const {
       
   167       return _find(m[a])->me;
       
   168     }
       
   169 
       
   170     bool join(T a, T b) {
       
   171 
       
   172       IIter ca = _find(m[a]);
       
   173       IIter cb = _find(m[b]);
       
   174 
       
   175       if ( ca == cb ) {
       
   176 	return false;
       
   177       }
       
   178 
       
   179       if ( ca->size > cb->size ) {
       
   180 
       
   181 	cb->parent = ca->parent;
       
   182 	ca->size += cb->size;
       
   183 	
       
   184 	ItemList &alist = *ca->my_class;
       
   185 	alist.splice(alist.end(),*cb->my_class);
       
   186 
       
   187 	classes.erase(cb->my_class);
       
   188 	cb->my_class = 0;
       
   189       }
       
   190       else {
       
   191 
       
   192 	ca->parent = cb->parent;
       
   193 	cb->size += ca->size;
       
   194 	
       
   195 	ItemList &blist = *cb->my_class;
       
   196 	blist.splice(blist.end(),*ca->my_class);
       
   197 
       
   198 	classes.erase(ca->my_class);
       
   199 	ca->my_class = 0;
       
   200       }
       
   201 
       
   202       return true;
       
   203     }
       
   204 
       
   205     int size(const T &a) const {
       
   206       return _find(m[a])->size;
       
   207     }
       
   208 
       
   209     
       
   210     void split(const T &a) {
       
   211 
       
   212       IIter ca = _find(m[a]);
       
   213  
       
   214       if ( ca->size == 1 )
       
   215 	return;
       
   216       
       
   217       CIter aclass = ca->my_class;
       
   218 
       
   219       for(IIter curr = ca; ++curr != aclass->end(); curr=ca) {
       
   220 	classes.push_back(ItemList());
       
   221 	CIter nl = --classes.end();
       
   222 	nl->splice(nl->end(), *aclass, curr);
       
   223 
       
   224 	curr->size=1;
       
   225 	curr->parent=curr;
       
   226 	curr->my_class = nl;
       
   227       }
       
   228 
       
   229       ca->size=1;
       
   230       return;
       
   231     }
       
   232 
       
   233     void erase(const T &a) {
       
   234 
       
   235       IIter ma = m[a];
       
   236       if (ma == 0) return;
       
   237 
       
   238       IIter la = _find(ma);
       
   239       if (la == ma) {
       
   240 	if (ma -> size == 1){
       
   241 	  classes.erase(ma->my_class);
       
   242 	  m.set(a,0);
       
   243 	  return;
       
   244 	}
       
   245 	++la;
       
   246 	la->size = ma->size - 1; 
       
   247 	la->my_class = ma->my_class;	
       
   248       }
       
   249 
       
   250       for (IIter i = la; i != la->my_class->end(); ++i) {
       
   251 	i->parent = la;
       
   252       }
       
   253 
       
   254       la->my_class->erase(ma);
       
   255       m.set(a,0);
       
   256     }
       
   257 
       
   258     void eraseClass(const T &a) {
       
   259       IIter ma = m[a];
       
   260       if (ma == 0) return;
       
   261 #     ifdef DEBUG
       
   262       CIter c = _find(ma)->my_class;
       
   263       for (IIter i=c->begin(); i!=c->end(); ++i)
       
   264 	m.set(i->me, 0);
       
   265 #     endif
       
   266       classes.erase(_find(ma)->my_class);
       
   267     }
       
   268 
       
   269 
       
   270     class ClassIt {
       
   271       friend class UnionFindEnum;
       
   272 
       
   273       CcIter i;
       
   274     public:
       
   275       ClassIt(Invalid): i(0) {}
       
   276       ClassIt() {}
       
   277       
       
   278       operator const T& () const { 
       
   279 	ItemList const &ll = *i;
       
   280 	return (ll.begin())->me; }
       
   281       bool operator == (ClassIt it) const {
       
   282 	return (i == it.i);
       
   283       }
       
   284       bool operator != (ClassIt it) const {
       
   285 	return (i != it.i);
       
   286       }
       
   287       bool operator < (ClassIt it) const {
       
   288 	return (i < it.i);
       
   289       }
       
   290 
       
   291       bool valid() const { return i != 0; }
       
   292     private:
       
   293       void first(const ClassList &l) { i = l.begin(); validate(l); }
       
   294       void next(const ClassList &l) {
       
   295 	++i; 
       
   296 	validate(l);
       
   297       }
       
   298       void validate(const ClassList &l) {
       
   299 	if ( i == l.end() ) 
       
   300 	  i = 0;
       
   301       }
       
   302     };
       
   303 
       
   304 
       
   305     ClassIt& first(ClassIt& it) const {
       
   306       it.first(classes);
       
   307       return it;
       
   308     }
       
   309 
       
   310     bool valid(ClassIt const &it) const {
       
   311       return it.valid(); 
       
   312     }
       
   313 
       
   314     ClassIt& next(ClassIt& it) const {
       
   315       it.next(classes);
       
   316       return it;
       
   317     }
       
   318 
       
   319 
       
   320     class ItemIt {
       
   321       friend class UnionFindEnum;
       
   322 
       
   323       IcIter i;
       
   324       const ItemList *l;
       
   325     public:
       
   326       ItemIt(Invalid): i(0) {}
       
   327       ItemIt() {}
       
   328       
       
   329       operator const T& () const { return i->me; }
       
   330       bool operator == (ItemIt it) const {
       
   331 	return (i == it.i);
       
   332       }
       
   333       bool operator != (ItemIt it) const {
       
   334 	return (i != it.i);
       
   335       }
       
   336       bool operator < (ItemIt it) const {
       
   337 	return (i < it.i);
       
   338       }
       
   339 
       
   340       bool valid() const { return i != 0; }
       
   341     private:
       
   342       void first(const ItemList &il) { l=&il; i = l->begin(); validate(); }
       
   343       void next() {
       
   344 	++i; 
       
   345 	validate();
       
   346       }
       
   347       void validate() {
       
   348 	if ( i == l->end() ) 
       
   349 	  i = 0;
       
   350       }
       
   351     };
       
   352 
       
   353 
       
   354     ItemIt& first(ItemIt& it, const T& a) const {
       
   355       it.first( * _find(m[a])->my_class );
       
   356       return it;
       
   357     }
       
   358 
       
   359     bool valid(ItemIt const &it) const {
       
   360       return it.valid(); 
       
   361     }
       
   362 
       
   363     ItemIt& next(ItemIt& it) const {
       
   364       it.next();
       
   365       return it;
       
   366     }
       
   367     
       
   368 
       
   369 
       
   370   };
       
   371 
    79 } //namespace hugo
   372 } //namespace hugo
    80 
   373 
    81 #endif //HUGO_UNION_FIND_H
   374 #endif //HUGO_UNION_FIND_H