diff -r bb8c4cd57900 -r 9f529abcaebf lemon/fib_heap.h --- a/lemon/fib_heap.h Thu Jun 11 22:16:11 2009 +0200 +++ b/lemon/fib_heap.h Thu Jun 11 23:13:24 2009 +0200 @@ -36,87 +36,88 @@ ///This class implements the \e Fibonacci \e heap data structure. A \e heap ///is a data structure for storing items with specified values called \e ///priorities in such a way that finding the item with minimum priority is - ///efficient. \c Compare specifies the ordering of the priorities. In a heap + ///efficient. \c CMP specifies the ordering of the priorities. In a heap ///one can change the priority of an item, add or erase an item, etc. /// ///The methods \ref increase and \ref erase are not efficient in a Fibonacci ///heap. In case of many calls to these operations, it is better to use a ///\ref BinHeap "binary heap". /// - ///\param _Prio Type of the priority of the items. - ///\param _ItemIntMap A read and writable Item int map, used internally + ///\param PRIO Type of the priority of the items. + ///\param IM A read and writable Item int map, used internally ///to handle the cross references. - ///\param _Compare A class for the ordering of the priorities. The - ///default is \c std::less<_Prio>. + ///\param CMP A class for the ordering of the priorities. The + ///default is \c std::less. /// ///\sa BinHeap ///\sa Dijkstra #ifdef DOXYGEN - template + template #else - template > + template > #endif class FibHeap { public: ///\e - typedef _ItemIntMap ItemIntMap; + typedef IM ItemIntMap; ///\e - typedef _Prio Prio; + typedef PRIO Prio; ///\e typedef typename ItemIntMap::Key Item; ///\e typedef std::pair Pair; ///\e - typedef _Compare Compare; + typedef CMP Compare; private: - class store; + class Store; - std::vector container; - int minimum; - ItemIntMap &iimap; - Compare comp; - int num_items; + std::vector _data; + int _minimum; + ItemIntMap &_iim; + Compare _comp; + int _num; public: - ///Status of the nodes + + /// \brief Type to represent the items states. + /// + /// Each Item element have a state associated to it. It may be "in heap", + /// "pre heap" or "post heap". The latter two are indifferent from the + /// heap's point of view, but may be useful to the user. + /// + /// The item-int map must be initialized in such way that it assigns + /// \c PRE_HEAP (-1) to any element to be put in the heap. enum State { - ///The node is in the heap - IN_HEAP = 0, - ///The node has never been in the heap - PRE_HEAP = -1, - ///The node was in the heap but it got out of it - POST_HEAP = -2 + IN_HEAP = 0, ///< = 0. + PRE_HEAP = -1, ///< = -1. + POST_HEAP = -2 ///< = -2. }; /// \brief The constructor /// - /// \c _iimap should be given to the constructor, since it is + /// \c map should be given to the constructor, since it is /// used internally to handle the cross references. - explicit FibHeap(ItemIntMap &_iimap) - : minimum(0), iimap(_iimap), num_items() {} + explicit FibHeap(ItemIntMap &map) + : _minimum(0), _iim(map), _num() {} /// \brief The constructor /// - /// \c _iimap should be given to the constructor, since it is used - /// internally to handle the cross references. \c _comp is an + /// \c map should be given to the constructor, since it is used + /// internally to handle the cross references. \c comp is an /// object for ordering of the priorities. - FibHeap(ItemIntMap &_iimap, const Compare &_comp) - : minimum(0), iimap(_iimap), comp(_comp), num_items() {} + FibHeap(ItemIntMap &map, const Compare &comp) + : _minimum(0), _iim(map), _comp(comp), _num() {} /// \brief The number of items stored in the heap. /// /// Returns the number of items stored in the heap. - int size() const { return num_items; } + int size() const { return _num; } /// \brief Checks if the heap stores no items. /// /// Returns \c true if and only if the heap stores no items. - bool empty() const { return num_items==0; } + bool empty() const { return _num==0; } /// \brief Make empty this heap. /// @@ -125,7 +126,7 @@ /// should first clear the heap and after that you should set the /// cross reference map for each item to \c PRE_HEAP. void clear() { - container.clear(); minimum = 0; num_items = 0; + _data.clear(); _minimum = 0; _num = 0; } /// \brief \c item gets to the heap with priority \c value independently @@ -135,10 +136,10 @@ /// stored in the heap and it calls \ref decrease(\c item, \c value) or /// \ref increase(\c item, \c value) otherwise. void set (const Item& item, const Prio& value) { - int i=iimap[item]; - if ( i >= 0 && container[i].in ) { - if ( comp(value, container[i].prio) ) decrease(item, value); - if ( comp(container[i].prio, value) ) increase(item, value); + int i=_iim[item]; + if ( i >= 0 && _data[i].in ) { + if ( _comp(value, _data[i].prio) ) decrease(item, value); + if ( _comp(_data[i].prio, value) ) increase(item, value); } else push(item, value); } @@ -147,33 +148,33 @@ /// Adds \c item to the heap with priority \c value. /// \pre \c item must not be stored in the heap. void push (const Item& item, const Prio& value) { - int i=iimap[item]; + int i=_iim[item]; if ( i < 0 ) { - int s=container.size(); - iimap.set( item, s ); - store st; + int s=_data.size(); + _iim.set( item, s ); + Store st; st.name=item; - container.push_back(st); + _data.push_back(st); i=s; } else { - container[i].parent=container[i].child=-1; - container[i].degree=0; - container[i].in=true; - container[i].marked=false; + _data[i].parent=_data[i].child=-1; + _data[i].degree=0; + _data[i].in=true; + _data[i].marked=false; } - if ( num_items ) { - container[container[minimum].right_neighbor].left_neighbor=i; - container[i].right_neighbor=container[minimum].right_neighbor; - container[minimum].right_neighbor=i; - container[i].left_neighbor=minimum; - if ( comp( value, container[minimum].prio) ) minimum=i; + if ( _num ) { + _data[_data[_minimum].right_neighbor].left_neighbor=i; + _data[i].right_neighbor=_data[_minimum].right_neighbor; + _data[_minimum].right_neighbor=i; + _data[i].left_neighbor=_minimum; + if ( _comp( value, _data[_minimum].prio) ) _minimum=i; } else { - container[i].right_neighbor=container[i].left_neighbor=i; - minimum=i; + _data[i].right_neighbor=_data[i].left_neighbor=i; + _minimum=i; } - container[i].prio=value; - ++num_items; + _data[i].prio=value; + ++_num; } /// \brief Returns the item with minimum priority relative to \c Compare. @@ -181,20 +182,20 @@ /// This method returns the item with minimum priority relative to \c /// Compare. /// \pre The heap must be nonempty. - Item top() const { return container[minimum].name; } + Item top() const { return _data[_minimum].name; } /// \brief Returns the minimum priority relative to \c Compare. /// /// It returns the minimum priority relative to \c Compare. /// \pre The heap must be nonempty. - const Prio& prio() const { return container[minimum].prio; } + const Prio& prio() const { return _data[_minimum].prio; } /// \brief Returns the priority of \c item. /// /// It returns the priority of \c item. /// \pre \c item must be in the heap. const Prio& operator[](const Item& item) const { - return container[iimap[item]].prio; + return _data[_iim[item]].prio; } /// \brief Deletes the item with minimum priority relative to \c Compare. @@ -204,33 +205,33 @@ /// \pre The heap must be non-empty. void pop() { /*The first case is that there are only one root.*/ - if ( container[minimum].left_neighbor==minimum ) { - container[minimum].in=false; - if ( container[minimum].degree!=0 ) { - makeroot(container[minimum].child); - minimum=container[minimum].child; + if ( _data[_minimum].left_neighbor==_minimum ) { + _data[_minimum].in=false; + if ( _data[_minimum].degree!=0 ) { + makeroot(_data[_minimum].child); + _minimum=_data[_minimum].child; balance(); } } else { - int right=container[minimum].right_neighbor; - unlace(minimum); - container[minimum].in=false; - if ( container[minimum].degree > 0 ) { - int left=container[minimum].left_neighbor; - int child=container[minimum].child; - int last_child=container[child].left_neighbor; + int right=_data[_minimum].right_neighbor; + unlace(_minimum); + _data[_minimum].in=false; + if ( _data[_minimum].degree > 0 ) { + int left=_data[_minimum].left_neighbor; + int child=_data[_minimum].child; + int last_child=_data[child].left_neighbor; makeroot(child); - container[left].right_neighbor=child; - container[child].left_neighbor=left; - container[right].left_neighbor=last_child; - container[last_child].right_neighbor=right; + _data[left].right_neighbor=child; + _data[child].left_neighbor=left; + _data[right].left_neighbor=last_child; + _data[last_child].right_neighbor=right; } - minimum=right; + _minimum=right; balance(); } // the case where there are more roots - --num_items; + --_num; } /// \brief Deletes \c item from the heap. @@ -238,15 +239,15 @@ /// This method deletes \c item from the heap, if \c item was already /// stored in the heap. It is quite inefficient in Fibonacci heaps. void erase (const Item& item) { - int i=iimap[item]; + int i=_iim[item]; - if ( i >= 0 && container[i].in ) { - if ( container[i].parent!=-1 ) { - int p=container[i].parent; + if ( i >= 0 && _data[i].in ) { + if ( _data[i].parent!=-1 ) { + int p=_data[i].parent; cut(i,p); cascade(p); } - minimum=i; //As if its prio would be -infinity + _minimum=i; //As if its prio would be -infinity pop(); } } @@ -257,15 +258,15 @@ /// \pre \c item must be stored in the heap with priority at least \c /// value relative to \c Compare. void decrease (Item item, const Prio& value) { - int i=iimap[item]; - container[i].prio=value; - int p=container[i].parent; + int i=_iim[item]; + _data[i].prio=value; + int p=_data[i].parent; - if ( p!=-1 && comp(value, container[p].prio) ) { + if ( p!=-1 && _comp(value, _data[p].prio) ) { cut(i,p); cascade(p); } - if ( comp(value, container[minimum].prio) ) minimum=i; + if ( _comp(value, _data[_minimum].prio) ) _minimum=i; } /// \brief Increases the priority of \c item to \c value. @@ -289,9 +290,9 @@ /// otherwise. In the latter case it is possible that \c item will /// get back to the heap again. State state(const Item &item) const { - int i=iimap[item]; + int i=_iim[item]; if( i>=0 ) { - if ( container[i].in ) i=0; + if ( _data[i].in ) i=0; else i=-2; } return State(i); @@ -301,7 +302,7 @@ /// /// Sets the state of the \c item in the heap. It can be used to /// manually clear the heap when it is important to achive the - /// better time complexity. + /// better time _complexity. /// \param i The item. /// \param st The state. It should not be \c IN_HEAP. void state(const Item& i, State st) { @@ -311,7 +312,7 @@ if (state(i) == IN_HEAP) { erase(i); } - iimap[i] = st; + _iim[i] = st; break; case IN_HEAP: break; @@ -322,7 +323,7 @@ void balance() { - int maxdeg=int( std::floor( 2.08*log(double(container.size()))))+1; + int maxdeg=int( std::floor( 2.08*log(double(_data.size()))))+1; std::vector A(maxdeg,-1); @@ -330,18 +331,18 @@ *Recall that now minimum does not point to the minimum prio element. *We set minimum to this during balance(). */ - int anchor=container[minimum].left_neighbor; - int next=minimum; + int anchor=_data[_minimum].left_neighbor; + int next=_minimum; bool end=false; do { int active=next; if ( anchor==active ) end=true; - int d=container[active].degree; - next=container[active].right_neighbor; + int d=_data[active].degree; + next=_data[active].right_neighbor; while (A[d]!=-1) { - if( comp(container[active].prio, container[A[d]].prio) ) { + if( _comp(_data[active].prio, _data[A[d]].prio) ) { fuse(active,A[d]); } else { fuse(A[d],active); @@ -354,21 +355,21 @@ } while ( !end ); - while ( container[minimum].parent >=0 ) - minimum=container[minimum].parent; - int s=minimum; - int m=minimum; + while ( _data[_minimum].parent >=0 ) + _minimum=_data[_minimum].parent; + int s=_minimum; + int m=_minimum; do { - if ( comp(container[s].prio, container[minimum].prio) ) minimum=s; - s=container[s].right_neighbor; + if ( _comp(_data[s].prio, _data[_minimum].prio) ) _minimum=s; + s=_data[s].right_neighbor; } while ( s != m ); } void makeroot(int c) { int s=c; do { - container[s].parent=-1; - s=container[s].right_neighbor; + _data[s].parent=-1; + s=_data[s].right_neighbor; } while ( s != c ); } @@ -376,32 +377,32 @@ /* *Replacing a from the children of b. */ - --container[b].degree; + --_data[b].degree; - if ( container[b].degree !=0 ) { - int child=container[b].child; + if ( _data[b].degree !=0 ) { + int child=_data[b].child; if ( child==a ) - container[b].child=container[child].right_neighbor; + _data[b].child=_data[child].right_neighbor; unlace(a); } /*Lacing a to the roots.*/ - int right=container[minimum].right_neighbor; - container[minimum].right_neighbor=a; - container[a].left_neighbor=minimum; - container[a].right_neighbor=right; - container[right].left_neighbor=a; + int right=_data[_minimum].right_neighbor; + _data[_minimum].right_neighbor=a; + _data[a].left_neighbor=_minimum; + _data[a].right_neighbor=right; + _data[right].left_neighbor=a; - container[a].parent=-1; - container[a].marked=false; + _data[a].parent=-1; + _data[a].marked=false; } void cascade(int a) { - if ( container[a].parent!=-1 ) { - int p=container[a].parent; + if ( _data[a].parent!=-1 ) { + int p=_data[a].parent; - if ( container[a].marked==false ) container[a].marked=true; + if ( _data[a].marked==false ) _data[a].marked=true; else { cut(a,p); cascade(p); @@ -413,38 +414,38 @@ unlace(b); /*Lacing b under a.*/ - container[b].parent=a; + _data[b].parent=a; - if (container[a].degree==0) { - container[b].left_neighbor=b; - container[b].right_neighbor=b; - container[a].child=b; + if (_data[a].degree==0) { + _data[b].left_neighbor=b; + _data[b].right_neighbor=b; + _data[a].child=b; } else { - int child=container[a].child; - int last_child=container[child].left_neighbor; - container[child].left_neighbor=b; - container[b].right_neighbor=child; - container[last_child].right_neighbor=b; - container[b].left_neighbor=last_child; + int child=_data[a].child; + int last_child=_data[child].left_neighbor; + _data[child].left_neighbor=b; + _data[b].right_neighbor=child; + _data[last_child].right_neighbor=b; + _data[b].left_neighbor=last_child; } - ++container[a].degree; + ++_data[a].degree; - container[b].marked=false; + _data[b].marked=false; } /* *It is invoked only if a has siblings. */ void unlace(int a) { - int leftn=container[a].left_neighbor; - int rightn=container[a].right_neighbor; - container[leftn].right_neighbor=rightn; - container[rightn].left_neighbor=leftn; + int leftn=_data[a].left_neighbor; + int rightn=_data[a].right_neighbor; + _data[leftn].right_neighbor=rightn; + _data[rightn].left_neighbor=leftn; } - class store { + class Store { friend class FibHeap; Item name; @@ -457,7 +458,7 @@ bool in; Prio prio; - store() : parent(-1), child(-1), degree(), marked(false), in(true) {} + Store() : parent(-1), child(-1), degree(), marked(false), in(true) {} }; };