1.1 --- a/lemon/bucket_heap.h Thu Nov 05 10:01:02 2009 +0100
1.2 +++ b/lemon/bucket_heap.h Thu Nov 05 10:23:16 2009 +0100
1.3 @@ -19,9 +19,9 @@
1.4 #ifndef LEMON_BUCKET_HEAP_H
1.5 #define LEMON_BUCKET_HEAP_H
1.6
1.7 -///\ingroup auxdat
1.8 +///\ingroup heaps
1.9 ///\file
1.10 -///\brief Bucket Heap implementation.
1.11 +///\brief Bucket heap implementation.
1.12
1.13 #include <vector>
1.14 #include <utility>
1.15 @@ -53,35 +53,41 @@
1.16
1.17 }
1.18
1.19 - /// \ingroup auxdat
1.20 + /// \ingroup heaps
1.21 ///
1.22 - /// \brief A Bucket Heap implementation.
1.23 + /// \brief Bucket heap data structure.
1.24 ///
1.25 - /// This class implements the \e bucket \e heap data structure. A \e heap
1.26 - /// is a data structure for storing items with specified values called \e
1.27 - /// priorities in such a way that finding the item with minimum priority is
1.28 - /// efficient. The bucket heap is very simple implementation, it can store
1.29 - /// only integer priorities and it stores for each priority in the
1.30 - /// \f$ [0..C) \f$ range a list of items. So it should be used only when
1.31 - /// the priorities are small. It is not intended to use as dijkstra heap.
1.32 + /// This class implements the \e bucket \e heap data structure.
1.33 + /// It practically conforms to the \ref concepts::Heap "heap concept",
1.34 + /// but it has some limitations.
1.35 ///
1.36 - /// \param IM A read and write Item int map, used internally
1.37 - /// to handle the cross references.
1.38 - /// \param MIN If the given parameter is false then instead of the
1.39 - /// minimum value the maximum can be retrivied with the top() and
1.40 - /// prio() member functions.
1.41 + /// The bucket heap is a very simple structure. It can store only
1.42 + /// \c int priorities and it maintains a list of items for each priority
1.43 + /// in the range <tt>[0..C)</tt>. So it should only be used when the
1.44 + /// priorities are small. It is not intended to use as a Dijkstra heap.
1.45 + ///
1.46 + /// \tparam IM A read-writable item map with \c int values, used
1.47 + /// internally to handle the cross references.
1.48 + /// \tparam MIN Indicate if the heap is a \e min-heap or a \e max-heap.
1.49 + /// The default is \e min-heap. If this parameter is set to \c false,
1.50 + /// then the comparison is reversed, so the top(), prio() and pop()
1.51 + /// functions deal with the item having maximum priority instead of the
1.52 + /// minimum.
1.53 + ///
1.54 + /// \sa SimpleBucketHeap
1.55 template <typename IM, bool MIN = true>
1.56 class BucketHeap {
1.57
1.58 public:
1.59 - /// \e
1.60 - typedef typename IM::Key Item;
1.61 - /// \e
1.62 +
1.63 + /// Type of the item-int map.
1.64 + typedef IM ItemIntMap;
1.65 + /// Type of the priorities.
1.66 typedef int Prio;
1.67 - /// \e
1.68 - typedef std::pair<Item, Prio> Pair;
1.69 - /// \e
1.70 - typedef IM ItemIntMap;
1.71 + /// Type of the items stored in the heap.
1.72 + typedef typename ItemIntMap::Key Item;
1.73 + /// Type of the item-priority pairs.
1.74 + typedef std::pair<Item,Prio> Pair;
1.75
1.76 private:
1.77
1.78 @@ -89,10 +95,10 @@
1.79
1.80 public:
1.81
1.82 - /// \brief Type to represent the items states.
1.83 + /// \brief Type to represent the states of the items.
1.84 ///
1.85 - /// Each Item element have a state associated to it. It may be "in heap",
1.86 - /// "pre heap" or "post heap". The latter two are indifferent from the
1.87 + /// Each item has a state associated to it. It can be "in heap",
1.88 + /// "pre-heap" or "post-heap". The latter two are indifferent from the
1.89 /// heap's point of view, but may be useful to the user.
1.90 ///
1.91 /// The item-int map must be initialized in such way that it assigns
1.92 @@ -104,37 +110,39 @@
1.93 };
1.94
1.95 public:
1.96 - /// \brief The constructor.
1.97 +
1.98 + /// \brief Constructor.
1.99 ///
1.100 - /// The constructor.
1.101 - /// \param map should be given to the constructor, since it is used
1.102 - /// internally to handle the cross references. The value of the map
1.103 - /// should be PRE_HEAP (-1) for each element.
1.104 + /// Constructor.
1.105 + /// \param map A map that assigns \c int values to the items.
1.106 + /// It is used internally to handle the cross references.
1.107 + /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
1.108 explicit BucketHeap(ItemIntMap &map) : _iim(map), _minimum(0) {}
1.109
1.110 - /// The number of items stored in the heap.
1.111 + /// \brief The number of items stored in the heap.
1.112 ///
1.113 - /// \brief Returns the number of items stored in the heap.
1.114 + /// This function returns the number of items stored in the heap.
1.115 int size() const { return _data.size(); }
1.116
1.117 - /// \brief Checks if the heap stores no items.
1.118 + /// \brief Check if the heap is empty.
1.119 ///
1.120 - /// Returns \c true if and only if the heap stores no items.
1.121 + /// This function returns \c true if the heap is empty.
1.122 bool empty() const { return _data.empty(); }
1.123
1.124 - /// \brief Make empty this heap.
1.125 + /// \brief Make the heap empty.
1.126 ///
1.127 - /// Make empty this heap. It does not change the cross reference
1.128 - /// map. If you want to reuse a heap what is not surely empty you
1.129 - /// should first clear the heap and after that you should set the
1.130 - /// cross reference map for each item to \c PRE_HEAP.
1.131 + /// This functon makes the heap empty.
1.132 + /// It does not change the cross reference map. If you want to reuse
1.133 + /// a heap that is not surely empty, you should first clear it and
1.134 + /// then you should set the cross reference map to \c PRE_HEAP
1.135 + /// for each item.
1.136 void clear() {
1.137 _data.clear(); _first.clear(); _minimum = 0;
1.138 }
1.139
1.140 private:
1.141
1.142 - void relocate_last(int idx) {
1.143 + void relocateLast(int idx) {
1.144 if (idx + 1 < int(_data.size())) {
1.145 _data[idx] = _data.back();
1.146 if (_data[idx].prev != -1) {
1.147 @@ -174,19 +182,24 @@
1.148 }
1.149
1.150 public:
1.151 +
1.152 /// \brief Insert a pair of item and priority into the heap.
1.153 ///
1.154 - /// Adds \c p.first to the heap with priority \c p.second.
1.155 + /// This function inserts \c p.first to the heap with priority
1.156 + /// \c p.second.
1.157 /// \param p The pair to insert.
1.158 + /// \pre \c p.first must not be stored in the heap.
1.159 void push(const Pair& p) {
1.160 push(p.first, p.second);
1.161 }
1.162
1.163 /// \brief Insert an item into the heap with the given priority.
1.164 ///
1.165 - /// Adds \c i to the heap with priority \c p.
1.166 + /// This function inserts the given item into the heap with the
1.167 + /// given priority.
1.168 /// \param i The item to insert.
1.169 /// \param p The priority of the item.
1.170 + /// \pre \e i must not be stored in the heap.
1.171 void push(const Item &i, const Prio &p) {
1.172 int idx = _data.size();
1.173 _iim[i] = idx;
1.174 @@ -197,10 +210,10 @@
1.175 }
1.176 }
1.177
1.178 - /// \brief Returns the item with minimum priority.
1.179 + /// \brief Return the item having minimum priority.
1.180 ///
1.181 - /// This method returns the item with minimum priority.
1.182 - /// \pre The heap must be nonempty.
1.183 + /// This function returns the item having minimum priority.
1.184 + /// \pre The heap must be non-empty.
1.185 Item top() const {
1.186 while (_first[_minimum] == -1) {
1.187 Direction::increase(_minimum);
1.188 @@ -208,10 +221,10 @@
1.189 return _data[_first[_minimum]].item;
1.190 }
1.191
1.192 - /// \brief Returns the minimum priority.
1.193 + /// \brief The minimum priority.
1.194 ///
1.195 - /// It returns the minimum priority.
1.196 - /// \pre The heap must be nonempty.
1.197 + /// This function returns the minimum priority.
1.198 + /// \pre The heap must be non-empty.
1.199 Prio prio() const {
1.200 while (_first[_minimum] == -1) {
1.201 Direction::increase(_minimum);
1.202 @@ -219,9 +232,9 @@
1.203 return _minimum;
1.204 }
1.205
1.206 - /// \brief Deletes the item with minimum priority.
1.207 + /// \brief Remove the item having minimum priority.
1.208 ///
1.209 - /// This method deletes the item with minimum priority from the heap.
1.210 + /// This function removes the item having minimum priority.
1.211 /// \pre The heap must be non-empty.
1.212 void pop() {
1.213 while (_first[_minimum] == -1) {
1.214 @@ -230,37 +243,38 @@
1.215 int idx = _first[_minimum];
1.216 _iim[_data[idx].item] = -2;
1.217 unlace(idx);
1.218 - relocate_last(idx);
1.219 + relocateLast(idx);
1.220 }
1.221
1.222 - /// \brief Deletes \c i from the heap.
1.223 + /// \brief Remove the given item from the heap.
1.224 ///
1.225 - /// This method deletes item \c i from the heap, if \c i was
1.226 - /// already stored in the heap.
1.227 - /// \param i The item to erase.
1.228 + /// This function removes the given item from the heap if it is
1.229 + /// already stored.
1.230 + /// \param i The item to delete.
1.231 + /// \pre \e i must be in the heap.
1.232 void erase(const Item &i) {
1.233 int idx = _iim[i];
1.234 _iim[_data[idx].item] = -2;
1.235 unlace(idx);
1.236 - relocate_last(idx);
1.237 + relocateLast(idx);
1.238 }
1.239
1.240 -
1.241 - /// \brief Returns the priority of \c i.
1.242 + /// \brief The priority of the given item.
1.243 ///
1.244 - /// This function returns the priority of item \c i.
1.245 - /// \pre \c i must be in the heap.
1.246 + /// This function returns the priority of the given item.
1.247 /// \param i The item.
1.248 + /// \pre \e i must be in the heap.
1.249 Prio operator[](const Item &i) const {
1.250 int idx = _iim[i];
1.251 return _data[idx].value;
1.252 }
1.253
1.254 - /// \brief \c i gets to the heap with priority \c p independently
1.255 - /// if \c i was already there.
1.256 + /// \brief Set the priority of an item or insert it, if it is
1.257 + /// not stored in the heap.
1.258 ///
1.259 - /// This method calls \ref push(\c i, \c p) if \c i is not stored
1.260 - /// in the heap and sets the priority of \c i to \c p otherwise.
1.261 + /// This method sets the priority of the given item if it is
1.262 + /// already stored in the heap. Otherwise it inserts the given
1.263 + /// item into the heap with the given priority.
1.264 /// \param i The item.
1.265 /// \param p The priority.
1.266 void set(const Item &i, const Prio &p) {
1.267 @@ -274,13 +288,12 @@
1.268 }
1.269 }
1.270
1.271 - /// \brief Decreases the priority of \c i to \c p.
1.272 + /// \brief Decrease the priority of an item to the given value.
1.273 ///
1.274 - /// This method decreases the priority of item \c i to \c p.
1.275 - /// \pre \c i must be stored in the heap with priority at least \c
1.276 - /// p relative to \c Compare.
1.277 + /// This function decreases the priority of an item to the given value.
1.278 /// \param i The item.
1.279 /// \param p The priority.
1.280 + /// \pre \e i must be stored in the heap with priority at least \e p.
1.281 void decrease(const Item &i, const Prio &p) {
1.282 int idx = _iim[i];
1.283 unlace(idx);
1.284 @@ -291,13 +304,12 @@
1.285 lace(idx);
1.286 }
1.287
1.288 - /// \brief Increases the priority of \c i to \c p.
1.289 + /// \brief Increase the priority of an item to the given value.
1.290 ///
1.291 - /// This method sets the priority of item \c i to \c p.
1.292 - /// \pre \c i must be stored in the heap with priority at most \c
1.293 - /// p relative to \c Compare.
1.294 + /// This function increases the priority of an item to the given value.
1.295 /// \param i The item.
1.296 /// \param p The priority.
1.297 + /// \pre \e i must be stored in the heap with priority at most \e p.
1.298 void increase(const Item &i, const Prio &p) {
1.299 int idx = _iim[i];
1.300 unlace(idx);
1.301 @@ -305,13 +317,13 @@
1.302 lace(idx);
1.303 }
1.304
1.305 - /// \brief Returns if \c item is in, has already been in, or has
1.306 - /// never been in the heap.
1.307 + /// \brief Return the state of an item.
1.308 ///
1.309 - /// This method returns PRE_HEAP if \c item has never been in the
1.310 - /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
1.311 - /// otherwise. In the latter case it is possible that \c item will
1.312 - /// get back to the heap again.
1.313 + /// This method returns \c PRE_HEAP if the given item has never
1.314 + /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
1.315 + /// and \c POST_HEAP otherwise.
1.316 + /// In the latter case it is possible that the item will get back
1.317 + /// to the heap again.
1.318 /// \param i The item.
1.319 State state(const Item &i) const {
1.320 int idx = _iim[i];
1.321 @@ -319,11 +331,11 @@
1.322 return State(idx);
1.323 }
1.324
1.325 - /// \brief Sets the state of the \c item in the heap.
1.326 + /// \brief Set the state of an item in the heap.
1.327 ///
1.328 - /// Sets the state of the \c item in the heap. It can be used to
1.329 - /// manually clear the heap when it is important to achive the
1.330 - /// better time complexity.
1.331 + /// This function sets the state of the given item in the heap.
1.332 + /// It can be used to manually clear the heap when it is important
1.333 + /// to achive better time complexity.
1.334 /// \param i The item.
1.335 /// \param st The state. It should not be \c IN_HEAP.
1.336 void state(const Item& i, State st) {
1.337 @@ -359,33 +371,44 @@
1.338
1.339 }; // class BucketHeap
1.340
1.341 - /// \ingroup auxdat
1.342 + /// \ingroup heaps
1.343 ///
1.344 - /// \brief A Simplified Bucket Heap implementation.
1.345 + /// \brief Simplified bucket heap data structure.
1.346 ///
1.347 /// This class implements a simplified \e bucket \e heap data
1.348 - /// structure. It does not provide some functionality but it faster
1.349 - /// and simplier data structure than the BucketHeap. The main
1.350 - /// difference is that the BucketHeap stores for every key a double
1.351 - /// linked list while this class stores just simple lists. In the
1.352 - /// other way it does not support erasing each elements just the
1.353 - /// minimal and it does not supports key increasing, decreasing.
1.354 + /// structure. It does not provide some functionality, but it is
1.355 + /// faster and simpler than BucketHeap. The main difference is
1.356 + /// that BucketHeap stores a doubly-linked list for each key while
1.357 + /// this class stores only simply-linked lists. It supports erasing
1.358 + /// only for the item having minimum priority and it does not support
1.359 + /// key increasing and decreasing.
1.360 ///
1.361 - /// \param IM A read and write Item int map, used internally
1.362 - /// to handle the cross references.
1.363 - /// \param MIN If the given parameter is false then instead of the
1.364 - /// minimum value the maximum can be retrivied with the top() and
1.365 - /// prio() member functions.
1.366 + /// Note that this implementation does not conform to the
1.367 + /// \ref concepts::Heap "heap concept" due to the lack of some
1.368 + /// functionality.
1.369 + ///
1.370 + /// \tparam IM A read-writable item map with \c int values, used
1.371 + /// internally to handle the cross references.
1.372 + /// \tparam MIN Indicate if the heap is a \e min-heap or a \e max-heap.
1.373 + /// The default is \e min-heap. If this parameter is set to \c false,
1.374 + /// then the comparison is reversed, so the top(), prio() and pop()
1.375 + /// functions deal with the item having maximum priority instead of the
1.376 + /// minimum.
1.377 ///
1.378 /// \sa BucketHeap
1.379 template <typename IM, bool MIN = true >
1.380 class SimpleBucketHeap {
1.381
1.382 public:
1.383 - typedef typename IM::Key Item;
1.384 +
1.385 + /// Type of the item-int map.
1.386 + typedef IM ItemIntMap;
1.387 + /// Type of the priorities.
1.388 typedef int Prio;
1.389 - typedef std::pair<Item, Prio> Pair;
1.390 - typedef IM ItemIntMap;
1.391 + /// Type of the items stored in the heap.
1.392 + typedef typename ItemIntMap::Key Item;
1.393 + /// Type of the item-priority pairs.
1.394 + typedef std::pair<Item,Prio> Pair;
1.395
1.396 private:
1.397
1.398 @@ -393,10 +416,10 @@
1.399
1.400 public:
1.401
1.402 - /// \brief Type to represent the items states.
1.403 + /// \brief Type to represent the states of the items.
1.404 ///
1.405 - /// Each Item element have a state associated to it. It may be "in heap",
1.406 - /// "pre heap" or "post heap". The latter two are indifferent from the
1.407 + /// Each item has a state associated to it. It can be "in heap",
1.408 + /// "pre-heap" or "post-heap". The latter two are indifferent from the
1.409 /// heap's point of view, but may be useful to the user.
1.410 ///
1.411 /// The item-int map must be initialized in such way that it assigns
1.412 @@ -409,48 +432,53 @@
1.413
1.414 public:
1.415
1.416 - /// \brief The constructor.
1.417 + /// \brief Constructor.
1.418 ///
1.419 - /// The constructor.
1.420 - /// \param map should be given to the constructor, since it is used
1.421 - /// internally to handle the cross references. The value of the map
1.422 - /// should be PRE_HEAP (-1) for each element.
1.423 + /// Constructor.
1.424 + /// \param map A map that assigns \c int values to the items.
1.425 + /// It is used internally to handle the cross references.
1.426 + /// The assigned value must be \c PRE_HEAP (<tt>-1</tt>) for each item.
1.427 explicit SimpleBucketHeap(ItemIntMap &map)
1.428 : _iim(map), _free(-1), _num(0), _minimum(0) {}
1.429
1.430 - /// \brief Returns the number of items stored in the heap.
1.431 + /// \brief The number of items stored in the heap.
1.432 ///
1.433 - /// The number of items stored in the heap.
1.434 + /// This function returns the number of items stored in the heap.
1.435 int size() const { return _num; }
1.436
1.437 - /// \brief Checks if the heap stores no items.
1.438 + /// \brief Check if the heap is empty.
1.439 ///
1.440 - /// Returns \c true if and only if the heap stores no items.
1.441 + /// This function returns \c true if the heap is empty.
1.442 bool empty() const { return _num == 0; }
1.443
1.444 - /// \brief Make empty this heap.
1.445 + /// \brief Make the heap empty.
1.446 ///
1.447 - /// Make empty this heap. It does not change the cross reference
1.448 - /// map. If you want to reuse a heap what is not surely empty you
1.449 - /// should first clear the heap and after that you should set the
1.450 - /// cross reference map for each item to \c PRE_HEAP.
1.451 + /// This functon makes the heap empty.
1.452 + /// It does not change the cross reference map. If you want to reuse
1.453 + /// a heap that is not surely empty, you should first clear it and
1.454 + /// then you should set the cross reference map to \c PRE_HEAP
1.455 + /// for each item.
1.456 void clear() {
1.457 _data.clear(); _first.clear(); _free = -1; _num = 0; _minimum = 0;
1.458 }
1.459
1.460 /// \brief Insert a pair of item and priority into the heap.
1.461 ///
1.462 - /// Adds \c p.first to the heap with priority \c p.second.
1.463 + /// This function inserts \c p.first to the heap with priority
1.464 + /// \c p.second.
1.465 /// \param p The pair to insert.
1.466 + /// \pre \c p.first must not be stored in the heap.
1.467 void push(const Pair& p) {
1.468 push(p.first, p.second);
1.469 }
1.470
1.471 /// \brief Insert an item into the heap with the given priority.
1.472 ///
1.473 - /// Adds \c i to the heap with priority \c p.
1.474 + /// This function inserts the given item into the heap with the
1.475 + /// given priority.
1.476 /// \param i The item to insert.
1.477 /// \param p The priority of the item.
1.478 + /// \pre \e i must not be stored in the heap.
1.479 void push(const Item &i, const Prio &p) {
1.480 int idx;
1.481 if (_free == -1) {
1.482 @@ -471,10 +499,10 @@
1.483 ++_num;
1.484 }
1.485
1.486 - /// \brief Returns the item with minimum priority.
1.487 + /// \brief Return the item having minimum priority.
1.488 ///
1.489 - /// This method returns the item with minimum priority.
1.490 - /// \pre The heap must be nonempty.
1.491 + /// This function returns the item having minimum priority.
1.492 + /// \pre The heap must be non-empty.
1.493 Item top() const {
1.494 while (_first[_minimum] == -1) {
1.495 Direction::increase(_minimum);
1.496 @@ -482,10 +510,10 @@
1.497 return _data[_first[_minimum]].item;
1.498 }
1.499
1.500 - /// \brief Returns the minimum priority.
1.501 + /// \brief The minimum priority.
1.502 ///
1.503 - /// It returns the minimum priority.
1.504 - /// \pre The heap must be nonempty.
1.505 + /// This function returns the minimum priority.
1.506 + /// \pre The heap must be non-empty.
1.507 Prio prio() const {
1.508 while (_first[_minimum] == -1) {
1.509 Direction::increase(_minimum);
1.510 @@ -493,9 +521,9 @@
1.511 return _minimum;
1.512 }
1.513
1.514 - /// \brief Deletes the item with minimum priority.
1.515 + /// \brief Remove the item having minimum priority.
1.516 ///
1.517 - /// This method deletes the item with minimum priority from the heap.
1.518 + /// This function removes the item having minimum priority.
1.519 /// \pre The heap must be non-empty.
1.520 void pop() {
1.521 while (_first[_minimum] == -1) {
1.522 @@ -509,16 +537,15 @@
1.523 --_num;
1.524 }
1.525
1.526 - /// \brief Returns the priority of \c i.
1.527 + /// \brief The priority of the given item.
1.528 ///
1.529 - /// This function returns the priority of item \c i.
1.530 - /// \warning This operator is not a constant time function
1.531 - /// because it scans the whole data structure to find the proper
1.532 - /// value.
1.533 - /// \pre \c i must be in the heap.
1.534 + /// This function returns the priority of the given item.
1.535 /// \param i The item.
1.536 + /// \pre \e i must be in the heap.
1.537 + /// \warning This operator is not a constant time function because
1.538 + /// it scans the whole data structure to find the proper value.
1.539 Prio operator[](const Item &i) const {
1.540 - for (int k = 0; k < _first.size(); ++k) {
1.541 + for (int k = 0; k < int(_first.size()); ++k) {
1.542 int idx = _first[k];
1.543 while (idx != -1) {
1.544 if (_data[idx].item == i) {
1.545 @@ -530,13 +557,13 @@
1.546 return -1;
1.547 }
1.548
1.549 - /// \brief Returns if \c item is in, has already been in, or has
1.550 - /// never been in the heap.
1.551 + /// \brief Return the state of an item.
1.552 ///
1.553 - /// This method returns PRE_HEAP if \c item has never been in the
1.554 - /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
1.555 - /// otherwise. In the latter case it is possible that \c item will
1.556 - /// get back to the heap again.
1.557 + /// This method returns \c PRE_HEAP if the given item has never
1.558 + /// been in the heap, \c IN_HEAP if it is in the heap at the moment,
1.559 + /// and \c POST_HEAP otherwise.
1.560 + /// In the latter case it is possible that the item will get back
1.561 + /// to the heap again.
1.562 /// \param i The item.
1.563 State state(const Item &i) const {
1.564 int idx = _iim[i];