1.1 --- a/lemon/bin_heap.h Thu Mar 05 10:13:20 2009 +0000
1.2 +++ b/lemon/bin_heap.h Sun Mar 29 23:08:20 2009 +0200
1.3 @@ -33,35 +33,36 @@
1.4 ///
1.5 ///\brief A Binary Heap implementation.
1.6 ///
1.7 - ///This class implements the \e binary \e heap data structure. A \e heap
1.8 - ///is a data structure for storing items with specified values called \e
1.9 - ///priorities in such a way that finding the item with minimum priority is
1.10 - ///efficient. \c Compare specifies the ordering of the priorities. In a heap
1.11 - ///one can change the priority of an item, add or erase an item, etc.
1.12 + ///This class implements the \e binary \e heap data structure.
1.13 + ///
1.14 + ///A \e heap is a data structure for storing items with specified values
1.15 + ///called \e priorities in such a way that finding the item with minimum
1.16 + ///priority is efficient. \c Comp specifies the ordering of the priorities.
1.17 + ///In a heap one can change the priority of an item, add or erase an
1.18 + ///item, etc.
1.19 ///
1.20 - ///\tparam _Prio Type of the priority of the items.
1.21 - ///\tparam _ItemIntMap A read and writable Item int map, used internally
1.22 + ///\tparam PR Type of the priority of the items.
1.23 + ///\tparam IM A read and writable item map with int values, used internally
1.24 ///to handle the cross references.
1.25 - ///\tparam _Compare A class for the ordering of the priorities. The
1.26 - ///default is \c std::less<_Prio>.
1.27 + ///\tparam Comp A functor class for the ordering of the priorities.
1.28 + ///The default is \c std::less<PR>.
1.29 ///
1.30 ///\sa FibHeap
1.31 ///\sa Dijkstra
1.32 - template <typename _Prio, typename _ItemIntMap,
1.33 - typename _Compare = std::less<_Prio> >
1.34 + template <typename PR, typename IM, typename Comp = std::less<PR> >
1.35 class BinHeap {
1.36
1.37 public:
1.38 ///\e
1.39 - typedef _ItemIntMap ItemIntMap;
1.40 + typedef IM ItemIntMap;
1.41 ///\e
1.42 - typedef _Prio Prio;
1.43 + typedef PR Prio;
1.44 ///\e
1.45 typedef typename ItemIntMap::Key Item;
1.46 ///\e
1.47 typedef std::pair<Item,Prio> Pair;
1.48 ///\e
1.49 - typedef _Compare Compare;
1.50 + typedef Comp Compare;
1.51
1.52 /// \brief Type to represent the items states.
1.53 ///
1.54 @@ -69,49 +70,49 @@
1.55 /// "pre heap" or "post heap". The latter two are indifferent from the
1.56 /// heap's point of view, but may be useful to the user.
1.57 ///
1.58 - /// The ItemIntMap \e should be initialized in such way that it maps
1.59 - /// PRE_HEAP (-1) to any element to be put in the heap...
1.60 + /// The item-int map must be initialized in such way that it assigns
1.61 + /// \c PRE_HEAP (<tt>-1</tt>) to any element to be put in the heap.
1.62 enum State {
1.63 - IN_HEAP = 0,
1.64 - PRE_HEAP = -1,
1.65 - POST_HEAP = -2
1.66 + IN_HEAP = 0, ///< \e
1.67 + PRE_HEAP = -1, ///< \e
1.68 + POST_HEAP = -2 ///< \e
1.69 };
1.70
1.71 private:
1.72 - std::vector<Pair> data;
1.73 - Compare comp;
1.74 - ItemIntMap &iim;
1.75 + std::vector<Pair> _data;
1.76 + Compare _comp;
1.77 + ItemIntMap &_iim;
1.78
1.79 public:
1.80 /// \brief The constructor.
1.81 ///
1.82 /// The constructor.
1.83 - /// \param _iim should be given to the constructor, since it is used
1.84 + /// \param map should be given to the constructor, since it is used
1.85 /// internally to handle the cross references. The value of the map
1.86 - /// should be PRE_HEAP (-1) for each element.
1.87 - explicit BinHeap(ItemIntMap &_iim) : iim(_iim) {}
1.88 + /// must be \c PRE_HEAP (<tt>-1</tt>) for every item.
1.89 + explicit BinHeap(ItemIntMap &map) : _iim(map) {}
1.90
1.91 /// \brief The constructor.
1.92 ///
1.93 /// The constructor.
1.94 - /// \param _iim should be given to the constructor, since it is used
1.95 + /// \param map should be given to the constructor, since it is used
1.96 /// internally to handle the cross references. The value of the map
1.97 /// should be PRE_HEAP (-1) for each element.
1.98 ///
1.99 - /// \param _comp The comparator function object.
1.100 - BinHeap(ItemIntMap &_iim, const Compare &_comp)
1.101 - : iim(_iim), comp(_comp) {}
1.102 + /// \param comp The comparator function object.
1.103 + BinHeap(ItemIntMap &map, const Compare &comp)
1.104 + : _iim(map), _comp(comp) {}
1.105
1.106
1.107 /// The number of items stored in the heap.
1.108 ///
1.109 /// \brief Returns the number of items stored in the heap.
1.110 - int size() const { return data.size(); }
1.111 + int size() const { return _data.size(); }
1.112
1.113 /// \brief Checks if the heap stores no items.
1.114 ///
1.115 /// Returns \c true if and only if the heap stores no items.
1.116 - bool empty() const { return data.empty(); }
1.117 + bool empty() const { return _data.empty(); }
1.118
1.119 /// \brief Make empty this heap.
1.120 ///
1.121 @@ -120,7 +121,7 @@
1.122 /// the heap and after that you should set the cross reference map for
1.123 /// each item to \c PRE_HEAP.
1.124 void clear() {
1.125 - data.clear();
1.126 + _data.clear();
1.127 }
1.128
1.129 private:
1.130 @@ -128,13 +129,13 @@
1.131
1.132 static int second_child(int i) { return 2*i+2; }
1.133 bool less(const Pair &p1, const Pair &p2) const {
1.134 - return comp(p1.second, p2.second);
1.135 + return _comp(p1.second, p2.second);
1.136 }
1.137
1.138 int bubble_up(int hole, Pair p) {
1.139 int par = parent(hole);
1.140 - while( hole>0 && less(p,data[par]) ) {
1.141 - move(data[par],hole);
1.142 + while( hole>0 && less(p,_data[par]) ) {
1.143 + move(_data[par],hole);
1.144 hole = par;
1.145 par = parent(hole);
1.146 }
1.147 @@ -145,18 +146,18 @@
1.148 int bubble_down(int hole, Pair p, int length) {
1.149 int child = second_child(hole);
1.150 while(child < length) {
1.151 - if( less(data[child-1], data[child]) ) {
1.152 + if( less(_data[child-1], _data[child]) ) {
1.153 --child;
1.154 }
1.155 - if( !less(data[child], p) )
1.156 + if( !less(_data[child], p) )
1.157 goto ok;
1.158 - move(data[child], hole);
1.159 + move(_data[child], hole);
1.160 hole = child;
1.161 child = second_child(hole);
1.162 }
1.163 child--;
1.164 - if( child<length && less(data[child], p) ) {
1.165 - move(data[child], hole);
1.166 + if( child<length && less(_data[child], p) ) {
1.167 + move(_data[child], hole);
1.168 hole=child;
1.169 }
1.170 ok:
1.171 @@ -165,8 +166,8 @@
1.172 }
1.173
1.174 void move(const Pair &p, int i) {
1.175 - data[i] = p;
1.176 - iim.set(p.first, i);
1.177 + _data[i] = p;
1.178 + _iim.set(p.first, i);
1.179 }
1.180
1.181 public:
1.182 @@ -175,8 +176,8 @@
1.183 /// Adds \c p.first to the heap with priority \c p.second.
1.184 /// \param p The pair to insert.
1.185 void push(const Pair &p) {
1.186 - int n = data.size();
1.187 - data.resize(n+1);
1.188 + int n = _data.size();
1.189 + _data.resize(n+1);
1.190 bubble_up(n, p);
1.191 }
1.192
1.193 @@ -193,7 +194,7 @@
1.194 /// Compare.
1.195 /// \pre The heap must be nonempty.
1.196 Item top() const {
1.197 - return data[0].first;
1.198 + return _data[0].first;
1.199 }
1.200
1.201 /// \brief Returns the minimum priority relative to \c Compare.
1.202 @@ -201,7 +202,7 @@
1.203 /// It returns the minimum priority relative to \c Compare.
1.204 /// \pre The heap must be nonempty.
1.205 Prio prio() const {
1.206 - return data[0].second;
1.207 + return _data[0].second;
1.208 }
1.209
1.210 /// \brief Deletes the item with minimum priority relative to \c Compare.
1.211 @@ -210,12 +211,12 @@
1.212 /// Compare from the heap.
1.213 /// \pre The heap must be non-empty.
1.214 void pop() {
1.215 - int n = data.size()-1;
1.216 - iim.set(data[0].first, POST_HEAP);
1.217 + int n = _data.size()-1;
1.218 + _iim.set(_data[0].first, POST_HEAP);
1.219 if (n > 0) {
1.220 - bubble_down(0, data[n], n);
1.221 + bubble_down(0, _data[n], n);
1.222 }
1.223 - data.pop_back();
1.224 + _data.pop_back();
1.225 }
1.226
1.227 /// \brief Deletes \c i from the heap.
1.228 @@ -224,26 +225,26 @@
1.229 /// \param i The item to erase.
1.230 /// \pre The item should be in the heap.
1.231 void erase(const Item &i) {
1.232 - int h = iim[i];
1.233 - int n = data.size()-1;
1.234 - iim.set(data[h].first, POST_HEAP);
1.235 + int h = _iim[i];
1.236 + int n = _data.size()-1;
1.237 + _iim.set(_data[h].first, POST_HEAP);
1.238 if( h < n ) {
1.239 - if ( bubble_up(h, data[n]) == h) {
1.240 - bubble_down(h, data[n], n);
1.241 + if ( bubble_up(h, _data[n]) == h) {
1.242 + bubble_down(h, _data[n], n);
1.243 }
1.244 }
1.245 - data.pop_back();
1.246 + _data.pop_back();
1.247 }
1.248
1.249
1.250 /// \brief Returns the priority of \c i.
1.251 ///
1.252 /// This function returns the priority of item \c i.
1.253 + /// \param i The item.
1.254 /// \pre \c i must be in the heap.
1.255 - /// \param i The item.
1.256 Prio operator[](const Item &i) const {
1.257 - int idx = iim[i];
1.258 - return data[idx].second;
1.259 + int idx = _iim[i];
1.260 + return _data[idx].second;
1.261 }
1.262
1.263 /// \brief \c i gets to the heap with priority \c p independently
1.264 @@ -254,40 +255,40 @@
1.265 /// \param i The item.
1.266 /// \param p The priority.
1.267 void set(const Item &i, const Prio &p) {
1.268 - int idx = iim[i];
1.269 + int idx = _iim[i];
1.270 if( idx < 0 ) {
1.271 push(i,p);
1.272 }
1.273 - else if( comp(p, data[idx].second) ) {
1.274 + else if( _comp(p, _data[idx].second) ) {
1.275 bubble_up(idx, Pair(i,p));
1.276 }
1.277 else {
1.278 - bubble_down(idx, Pair(i,p), data.size());
1.279 + bubble_down(idx, Pair(i,p), _data.size());
1.280 }
1.281 }
1.282
1.283 /// \brief Decreases the priority of \c i to \c p.
1.284 ///
1.285 /// This method decreases the priority of item \c i to \c p.
1.286 + /// \param i The item.
1.287 + /// \param p The priority.
1.288 /// \pre \c i must be stored in the heap with priority at least \c
1.289 /// p relative to \c Compare.
1.290 - /// \param i The item.
1.291 - /// \param p The priority.
1.292 void decrease(const Item &i, const Prio &p) {
1.293 - int idx = iim[i];
1.294 + int idx = _iim[i];
1.295 bubble_up(idx, Pair(i,p));
1.296 }
1.297
1.298 /// \brief Increases the priority of \c i to \c p.
1.299 ///
1.300 /// This method sets the priority of item \c i to \c p.
1.301 + /// \param i The item.
1.302 + /// \param p The priority.
1.303 /// \pre \c i must be stored in the heap with priority at most \c
1.304 /// p relative to \c Compare.
1.305 - /// \param i The item.
1.306 - /// \param p The priority.
1.307 void increase(const Item &i, const Prio &p) {
1.308 - int idx = iim[i];
1.309 - bubble_down(idx, Pair(i,p), data.size());
1.310 + int idx = _iim[i];
1.311 + bubble_down(idx, Pair(i,p), _data.size());
1.312 }
1.313
1.314 /// \brief Returns if \c item is in, has already been in, or has
1.315 @@ -299,7 +300,7 @@
1.316 /// get back to the heap again.
1.317 /// \param i The item.
1.318 State state(const Item &i) const {
1.319 - int s = iim[i];
1.320 + int s = _iim[i];
1.321 if( s>=0 )
1.322 s=0;
1.323 return State(s);
1.324 @@ -319,7 +320,7 @@
1.325 if (state(i) == IN_HEAP) {
1.326 erase(i);
1.327 }
1.328 - iim[i] = st;
1.329 + _iim[i] = st;
1.330 break;
1.331 case IN_HEAP:
1.332 break;
1.333 @@ -333,10 +334,10 @@
1.334 /// \c i item will out of the heap and \c j will be in the heap
1.335 /// with the same prioriority as prevoiusly the \c i item.
1.336 void replace(const Item& i, const Item& j) {
1.337 - int idx = iim[i];
1.338 - iim.set(i, iim[j]);
1.339 - iim.set(j, idx);
1.340 - data[idx].first = j;
1.341 + int idx = _iim[i];
1.342 + _iim.set(i, _iim[j]);
1.343 + _iim.set(j, idx);
1.344 + _data[idx].first = j;
1.345 }
1.346
1.347 }; // class BinHeap