1.1 --- a/lemon/bin_heap.h Fri Oct 16 10:21:37 2009 +0200
1.2 +++ b/lemon/bin_heap.h Thu Nov 05 15:50:01 2009 +0100
1.3 @@ -2,7 +2,7 @@
1.4 *
1.5 * This file is a part of LEMON, a generic C++ optimization library.
1.6 *
1.7 - * Copyright (C) 2003-2008
1.8 + * Copyright (C) 2003-2009
1.9 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.10 * (Egervary Research Group on Combinatorial Optimization, EGRES).
1.11 *
1.12 @@ -19,9 +19,9 @@
1.13 #ifndef LEMON_BIN_HEAP_H
1.14 #define LEMON_BIN_HEAP_H
1.15
1.16 -///\ingroup auxdat
1.17 +///\ingroup heaps
1.18 ///\file
1.19 -///\brief Binary Heap implementation.
1.20 +///\brief Binary heap implementation.
1.21
1.22 #include <vector>
1.23 #include <utility>
1.24 @@ -29,112 +29,110 @@
1.25
1.26 namespace lemon {
1.27
1.28 - ///\ingroup auxdat
1.29 + /// \ingroup heaps
1.30 ///
1.31 - ///\brief A Binary Heap implementation.
1.32 + /// \brief Binary heap data structure.
1.33 ///
1.34 - ///This class implements the \e binary \e heap data structure. A \e heap
1.35 - ///is a data structure for storing items with specified values called \e
1.36 - ///priorities in such a way that finding the item with minimum priority is
1.37 - ///efficient. \c Compare specifies the ordering of the priorities. In a heap
1.38 - ///one can change the priority of an item, add or erase an item, etc.
1.39 + /// This class implements the \e binary \e heap data structure.
1.40 + /// It fully conforms to the \ref concepts::Heap "heap concept".
1.41 ///
1.42 - ///\tparam _Prio Type of the priority of the items.
1.43 - ///\tparam _ItemIntMap A read and writable Item int map, used internally
1.44 - ///to handle the cross references.
1.45 - ///\tparam _Compare A class for the ordering of the priorities. The
1.46 - ///default is \c std::less<_Prio>.
1.47 - ///
1.48 - ///\sa FibHeap
1.49 - ///\sa Dijkstra
1.50 - template <typename _Prio, typename _ItemIntMap,
1.51 - typename _Compare = std::less<_Prio> >
1.52 + /// \tparam PR Type of the priorities of the items.
1.53 + /// \tparam IM A read-writable item map with \c int values, used
1.54 + /// internally to handle the cross references.
1.55 + /// \tparam CMP A functor class for comparing the priorities.
1.56 + /// The default is \c std::less<PR>.
1.57 +#ifdef DOXYGEN
1.58 + template <typename PR, typename IM, typename CMP>
1.59 +#else
1.60 + template <typename PR, typename IM, typename CMP = std::less<PR> >
1.61 +#endif
1.62 class BinHeap {
1.63 + public:
1.64
1.65 - public:
1.66 - ///\e
1.67 - typedef _ItemIntMap ItemIntMap;
1.68 - ///\e
1.69 - typedef _Prio Prio;
1.70 - ///\e
1.71 + /// Type of the item-int map.
1.72 + typedef IM ItemIntMap;
1.73 + /// Type of the priorities.
1.74 + typedef PR Prio;
1.75 + /// Type of the items stored in the heap.
1.76 typedef typename ItemIntMap::Key Item;
1.77 - ///\e
1.78 + /// Type of the item-priority pairs.
1.79 typedef std::pair<Item,Prio> Pair;
1.80 - ///\e
1.81 - typedef _Compare Compare;
1.82 + /// Functor type for comparing the priorities.
1.83 + typedef CMP Compare;
1.84
1.85 - /// \brief Type to represent the items states.
1.86 + /// \brief Type to represent the states of the items.
1.87 ///
1.88 - /// Each Item element have a state associated to it. It may be "in heap",
1.89 - /// "pre heap" or "post heap". The latter two are indifferent from the
1.90 + /// Each item has a state associated to it. It can be "in heap",
1.91 + /// "pre-heap" or "post-heap". The latter two are indifferent from the
1.92 /// heap's point of view, but may be useful to the user.
1.93 ///
1.94 - /// The ItemIntMap \e should be initialized in such way that it maps
1.95 - /// PRE_HEAP (-1) to any element to be put in the heap...
1.96 + /// The item-int map must be initialized in such way that it assigns
1.97 + /// \c PRE_HEAP (<tt>-1</tt>) to any element to be put in the heap.
1.98 enum State {
1.99 - IN_HEAP = 0,
1.100 - PRE_HEAP = -1,
1.101 - POST_HEAP = -2
1.102 + IN_HEAP = 0, ///< = 0.
1.103 + PRE_HEAP = -1, ///< = -1.
1.104 + POST_HEAP = -2 ///< = -2.
1.105 };
1.106
1.107 private:
1.108 - std::vector<Pair> data;
1.109 - Compare comp;
1.110 - ItemIntMap &iim;
1.111 + std::vector<Pair> _data;
1.112 + Compare _comp;
1.113 + ItemIntMap &_iim;
1.114
1.115 public:
1.116 - /// \brief The constructor.
1.117 +
1.118 + /// \brief Constructor.
1.119 ///
1.120 - /// The constructor.
1.121 - /// \param _iim should be given to the constructor, since it is used
1.122 - /// internally to handle the cross references. The value of the map
1.123 - /// should be PRE_HEAP (-1) for each element.
1.124 - explicit BinHeap(ItemIntMap &_iim) : iim(_iim) {}
1.125 + /// Constructor.
1.126 + /// \param map A map that assigns \c int values to the items.
1.127 + /// It is used internally to handle the cross references.
1.128 + /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
1.129 + explicit BinHeap(ItemIntMap &map) : _iim(map) {}
1.130
1.131 - /// \brief The constructor.
1.132 + /// \brief Constructor.
1.133 ///
1.134 - /// The constructor.
1.135 - /// \param _iim should be given to the constructor, since it is used
1.136 - /// internally to handle the cross references. The value of the map
1.137 - /// should be PRE_HEAP (-1) for each element.
1.138 + /// Constructor.
1.139 + /// \param map A map that assigns \c int values to the items.
1.140 + /// It is used internally to handle the cross references.
1.141 + /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
1.142 + /// \param comp The function object used for comparing the priorities.
1.143 + BinHeap(ItemIntMap &map, const Compare &comp)
1.144 + : _iim(map), _comp(comp) {}
1.145 +
1.146 +
1.147 + /// \brief The number of items stored in the heap.
1.148 ///
1.149 - /// \param _comp The comparator function object.
1.150 - BinHeap(ItemIntMap &_iim, const Compare &_comp)
1.151 - : iim(_iim), comp(_comp) {}
1.152 + /// This function returns the number of items stored in the heap.
1.153 + int size() const { return _data.size(); }
1.154
1.155 + /// \brief Check if the heap is empty.
1.156 + ///
1.157 + /// This function returns \c true if the heap is empty.
1.158 + bool empty() const { return _data.empty(); }
1.159
1.160 - /// The number of items stored in the heap.
1.161 + /// \brief Make the heap empty.
1.162 ///
1.163 - /// \brief Returns the number of items stored in the heap.
1.164 - int size() const { return data.size(); }
1.165 -
1.166 - /// \brief Checks if the heap stores no items.
1.167 - ///
1.168 - /// Returns \c true if and only if the heap stores no items.
1.169 - bool empty() const { return data.empty(); }
1.170 -
1.171 - /// \brief Make empty this heap.
1.172 - ///
1.173 - /// Make empty this heap. It does not change the cross reference map.
1.174 - /// If you want to reuse what is not surely empty you should first clear
1.175 - /// the heap and after that you should set the cross reference map for
1.176 - /// each item to \c PRE_HEAP.
1.177 + /// This functon makes the heap empty.
1.178 + /// It does not change the cross reference map. If you want to reuse
1.179 + /// a heap that is not surely empty, you should first clear it and
1.180 + /// then you should set the cross reference map to \c PRE_HEAP
1.181 + /// for each item.
1.182 void clear() {
1.183 - data.clear();
1.184 + _data.clear();
1.185 }
1.186
1.187 private:
1.188 static int parent(int i) { return (i-1)/2; }
1.189
1.190 - static int second_child(int i) { return 2*i+2; }
1.191 + static int secondChild(int i) { return 2*i+2; }
1.192 bool less(const Pair &p1, const Pair &p2) const {
1.193 - return comp(p1.second, p2.second);
1.194 + return _comp(p1.second, p2.second);
1.195 }
1.196
1.197 - int bubble_up(int hole, Pair p) {
1.198 + int bubbleUp(int hole, Pair p) {
1.199 int par = parent(hole);
1.200 - while( hole>0 && less(p,data[par]) ) {
1.201 - move(data[par],hole);
1.202 + while( hole>0 && less(p,_data[par]) ) {
1.203 + move(_data[par],hole);
1.204 hole = par;
1.205 par = parent(hole);
1.206 }
1.207 @@ -142,21 +140,21 @@
1.208 return hole;
1.209 }
1.210
1.211 - int bubble_down(int hole, Pair p, int length) {
1.212 - int child = second_child(hole);
1.213 + int bubbleDown(int hole, Pair p, int length) {
1.214 + int child = secondChild(hole);
1.215 while(child < length) {
1.216 - if( less(data[child-1], data[child]) ) {
1.217 + if( less(_data[child-1], _data[child]) ) {
1.218 --child;
1.219 }
1.220 - if( !less(data[child], p) )
1.221 + if( !less(_data[child], p) )
1.222 goto ok;
1.223 - move(data[child], hole);
1.224 + move(_data[child], hole);
1.225 hole = child;
1.226 - child = second_child(hole);
1.227 + child = secondChild(hole);
1.228 }
1.229 child--;
1.230 - if( child<length && less(data[child], p) ) {
1.231 - move(data[child], hole);
1.232 + if( child<length && less(_data[child], p) ) {
1.233 + move(_data[child], hole);
1.234 hole=child;
1.235 }
1.236 ok:
1.237 @@ -165,151 +163,153 @@
1.238 }
1.239
1.240 void move(const Pair &p, int i) {
1.241 - data[i] = p;
1.242 - iim.set(p.first, i);
1.243 + _data[i] = p;
1.244 + _iim.set(p.first, i);
1.245 }
1.246
1.247 public:
1.248 +
1.249 /// \brief Insert a pair of item and priority into the heap.
1.250 ///
1.251 - /// Adds \c p.first to the heap with priority \c p.second.
1.252 + /// This function inserts \c p.first to the heap with priority
1.253 + /// \c p.second.
1.254 /// \param p The pair to insert.
1.255 + /// \pre \c p.first must not be stored in the heap.
1.256 void push(const Pair &p) {
1.257 - int n = data.size();
1.258 - data.resize(n+1);
1.259 - bubble_up(n, p);
1.260 + int n = _data.size();
1.261 + _data.resize(n+1);
1.262 + bubbleUp(n, p);
1.263 }
1.264
1.265 - /// \brief Insert an item into the heap with the given heap.
1.266 + /// \brief Insert an item into the heap with the given priority.
1.267 ///
1.268 - /// Adds \c i to the heap with priority \c p.
1.269 + /// This function inserts the given item into the heap with the
1.270 + /// given priority.
1.271 /// \param i The item to insert.
1.272 /// \param p The priority of the item.
1.273 + /// \pre \e i must not be stored in the heap.
1.274 void push(const Item &i, const Prio &p) { push(Pair(i,p)); }
1.275
1.276 - /// \brief Returns the item with minimum priority relative to \c Compare.
1.277 + /// \brief Return the item having minimum priority.
1.278 ///
1.279 - /// This method returns the item with minimum priority relative to \c
1.280 - /// Compare.
1.281 - /// \pre The heap must be nonempty.
1.282 + /// This function returns the item having minimum priority.
1.283 + /// \pre The heap must be non-empty.
1.284 Item top() const {
1.285 - return data[0].first;
1.286 + return _data[0].first;
1.287 }
1.288
1.289 - /// \brief Returns the minimum priority relative to \c Compare.
1.290 + /// \brief The minimum priority.
1.291 ///
1.292 - /// It returns the minimum priority relative to \c Compare.
1.293 - /// \pre The heap must be nonempty.
1.294 + /// This function returns the minimum priority.
1.295 + /// \pre The heap must be non-empty.
1.296 Prio prio() const {
1.297 - return data[0].second;
1.298 + return _data[0].second;
1.299 }
1.300
1.301 - /// \brief Deletes the item with minimum priority relative to \c Compare.
1.302 + /// \brief Remove the item having minimum priority.
1.303 ///
1.304 - /// This method deletes the item with minimum priority relative to \c
1.305 - /// Compare from the heap.
1.306 + /// This function removes the item having minimum priority.
1.307 /// \pre The heap must be non-empty.
1.308 void pop() {
1.309 - int n = data.size()-1;
1.310 - iim.set(data[0].first, POST_HEAP);
1.311 + int n = _data.size()-1;
1.312 + _iim.set(_data[0].first, POST_HEAP);
1.313 if (n > 0) {
1.314 - bubble_down(0, data[n], n);
1.315 + bubbleDown(0, _data[n], n);
1.316 }
1.317 - data.pop_back();
1.318 + _data.pop_back();
1.319 }
1.320
1.321 - /// \brief Deletes \c i from the heap.
1.322 + /// \brief Remove the given item from the heap.
1.323 ///
1.324 - /// This method deletes item \c i from the heap.
1.325 - /// \param i The item to erase.
1.326 - /// \pre The item should be in the heap.
1.327 + /// This function removes the given item from the heap if it is
1.328 + /// already stored.
1.329 + /// \param i The item to delete.
1.330 + /// \pre \e i must be in the heap.
1.331 void erase(const Item &i) {
1.332 - int h = iim[i];
1.333 - int n = data.size()-1;
1.334 - iim.set(data[h].first, POST_HEAP);
1.335 + int h = _iim[i];
1.336 + int n = _data.size()-1;
1.337 + _iim.set(_data[h].first, POST_HEAP);
1.338 if( h < n ) {
1.339 - if ( bubble_up(h, data[n]) == h) {
1.340 - bubble_down(h, data[n], n);
1.341 + if ( bubbleUp(h, _data[n]) == h) {
1.342 + bubbleDown(h, _data[n], n);
1.343 }
1.344 }
1.345 - data.pop_back();
1.346 + _data.pop_back();
1.347 }
1.348
1.349 -
1.350 - /// \brief Returns the priority of \c i.
1.351 + /// \brief The priority of the given item.
1.352 ///
1.353 - /// This function returns the priority of item \c i.
1.354 - /// \pre \c i must be in the heap.
1.355 + /// This function returns the priority of the given item.
1.356 /// \param i The item.
1.357 + /// \pre \e i must be in the heap.
1.358 Prio operator[](const Item &i) const {
1.359 - int idx = iim[i];
1.360 - return data[idx].second;
1.361 + int idx = _iim[i];
1.362 + return _data[idx].second;
1.363 }
1.364
1.365 - /// \brief \c i gets to the heap with priority \c p independently
1.366 - /// if \c i was already there.
1.367 + /// \brief Set the priority of an item or insert it, if it is
1.368 + /// not stored in the heap.
1.369 ///
1.370 - /// This method calls \ref push(\c i, \c p) if \c i is not stored
1.371 - /// in the heap and sets the priority of \c i to \c p otherwise.
1.372 + /// This method sets the priority of the given item if it is
1.373 + /// already stored in the heap. Otherwise it inserts the given
1.374 + /// item into the heap with the given priority.
1.375 /// \param i The item.
1.376 /// \param p The priority.
1.377 void set(const Item &i, const Prio &p) {
1.378 - int idx = iim[i];
1.379 + int idx = _iim[i];
1.380 if( idx < 0 ) {
1.381 push(i,p);
1.382 }
1.383 - else if( comp(p, data[idx].second) ) {
1.384 - bubble_up(idx, Pair(i,p));
1.385 + else if( _comp(p, _data[idx].second) ) {
1.386 + bubbleUp(idx, Pair(i,p));
1.387 }
1.388 else {
1.389 - bubble_down(idx, Pair(i,p), data.size());
1.390 + bubbleDown(idx, Pair(i,p), _data.size());
1.391 }
1.392 }
1.393
1.394 - /// \brief Decreases the priority of \c i to \c p.
1.395 + /// \brief Decrease the priority of an item to the given value.
1.396 ///
1.397 - /// This method decreases the priority of item \c i to \c p.
1.398 - /// \pre \c i must be stored in the heap with priority at least \c
1.399 - /// p relative to \c Compare.
1.400 + /// This function decreases the priority of an item to the given value.
1.401 /// \param i The item.
1.402 /// \param p The priority.
1.403 + /// \pre \e i must be stored in the heap with priority at least \e p.
1.404 void decrease(const Item &i, const Prio &p) {
1.405 - int idx = iim[i];
1.406 - bubble_up(idx, Pair(i,p));
1.407 + int idx = _iim[i];
1.408 + bubbleUp(idx, Pair(i,p));
1.409 }
1.410
1.411 - /// \brief Increases the priority of \c i to \c p.
1.412 + /// \brief Increase the priority of an item to the given value.
1.413 ///
1.414 - /// This method sets the priority of item \c i to \c p.
1.415 - /// \pre \c i must be stored in the heap with priority at most \c
1.416 - /// p relative to \c Compare.
1.417 + /// This function increases the priority of an item to the given value.
1.418 /// \param i The item.
1.419 /// \param p The priority.
1.420 + /// \pre \e i must be stored in the heap with priority at most \e p.
1.421 void increase(const Item &i, const Prio &p) {
1.422 - int idx = iim[i];
1.423 - bubble_down(idx, Pair(i,p), data.size());
1.424 + int idx = _iim[i];
1.425 + bubbleDown(idx, Pair(i,p), _data.size());
1.426 }
1.427
1.428 - /// \brief Returns if \c item is in, has already been in, or has
1.429 - /// never been in the heap.
1.430 + /// \brief Return the state of an item.
1.431 ///
1.432 - /// This method returns PRE_HEAP if \c item has never been in the
1.433 - /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
1.434 - /// otherwise. In the latter case it is possible that \c item will
1.435 - /// get back to the heap again.
1.436 + /// This method returns \c PRE_HEAP if the given item has never
1.437 + /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
1.438 + /// and \c POST_HEAP otherwise.
1.439 + /// In the latter case it is possible that the item will get back
1.440 + /// to the heap again.
1.441 /// \param i The item.
1.442 State state(const Item &i) const {
1.443 - int s = iim[i];
1.444 + int s = _iim[i];
1.445 if( s>=0 )
1.446 s=0;
1.447 return State(s);
1.448 }
1.449
1.450 - /// \brief Sets the state of the \c item in the heap.
1.451 + /// \brief Set the state of an item in the heap.
1.452 ///
1.453 - /// Sets the state of the \c item in the heap. It can be used to
1.454 - /// manually clear the heap when it is important to achive the
1.455 - /// better time complexity.
1.456 + /// This function sets the state of the given item in the heap.
1.457 + /// It can be used to manually clear the heap when it is important
1.458 + /// to achive better time complexity.
1.459 /// \param i The item.
1.460 /// \param st The state. It should not be \c IN_HEAP.
1.461 void state(const Item& i, State st) {
1.462 @@ -319,24 +319,25 @@
1.463 if (state(i) == IN_HEAP) {
1.464 erase(i);
1.465 }
1.466 - iim[i] = st;
1.467 + _iim[i] = st;
1.468 break;
1.469 case IN_HEAP:
1.470 break;
1.471 }
1.472 }
1.473
1.474 - /// \brief Replaces an item in the heap.
1.475 + /// \brief Replace an item in the heap.
1.476 ///
1.477 - /// The \c i item is replaced with \c j item. The \c i item should
1.478 - /// be in the heap, while the \c j should be out of the heap. The
1.479 - /// \c i item will out of the heap and \c j will be in the heap
1.480 - /// with the same prioriority as prevoiusly the \c i item.
1.481 + /// This function replaces item \c i with item \c j.
1.482 + /// Item \c i must be in the heap, while \c j must be out of the heap.
1.483 + /// After calling this method, item \c i will be out of the
1.484 + /// heap and \c j will be in the heap with the same prioriority
1.485 + /// as item \c i had before.
1.486 void replace(const Item& i, const Item& j) {
1.487 - int idx = iim[i];
1.488 - iim.set(i, iim[j]);
1.489 - iim.set(j, idx);
1.490 - data[idx].first = j;
1.491 + int idx = _iim[i];
1.492 + _iim.set(i, _iim[j]);
1.493 + _iim.set(j, idx);
1.494 + _data[idx].first = j;
1.495 }
1.496
1.497 }; // class BinHeap