1.1 --- a/lemon/linear_heap.h Tue Apr 04 17:43:23 2006 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,520 +0,0 @@
1.4 -/* -*- C++ -*-
1.5 - *
1.6 - * This file is a part of LEMON, a generic C++ optimization library
1.7 - *
1.8 - * Copyright (C) 2003-2006
1.9 - * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.10 - * (Egervary Research Group on Combinatorial Optimization, EGRES).
1.11 - *
1.12 - * Permission to use, modify and distribute this software is granted
1.13 - * provided that this copyright notice appears in all copies. For
1.14 - * precise terms see the accompanying LICENSE file.
1.15 - *
1.16 - * This software is provided "AS IS" with no warranty of any kind,
1.17 - * express or implied, and with no claim as to its suitability for any
1.18 - * purpose.
1.19 - *
1.20 - */
1.21 -
1.22 -#ifndef LEMON_LINEAR_HEAP_H
1.23 -#define LEMON_LINEAR_HEAP_H
1.24 -
1.25 -///\ingroup auxdat
1.26 -///\file
1.27 -///\brief Binary Heap implementation.
1.28 -
1.29 -#include <vector>
1.30 -#include <utility>
1.31 -#include <functional>
1.32 -
1.33 -namespace lemon {
1.34 -
1.35 - /// \ingroup auxdat
1.36 -
1.37 - /// \brief A Linear Heap implementation.
1.38 - ///
1.39 - /// This class implements the \e linear \e heap data structure. A \e heap
1.40 - /// is a data structure for storing items with specified values called \e
1.41 - /// priorities in such a way that finding the item with minimum priority is
1.42 - /// efficient. The linear heap is very simple implementation, it can store
1.43 - /// only integer priorities and it stores for each priority in the [0..C]
1.44 - /// range a list of items. So it should be used only when the priorities
1.45 - /// are small. It is not intended to use as dijkstra heap.
1.46 - ///
1.47 - /// \param _Item Type of the items to be stored.
1.48 - /// \param _ItemIntMap A read and writable Item int map, used internally
1.49 - /// to handle the cross references.
1.50 - /// \param minimize If the given parameter is true then the heap gives back
1.51 - /// the lowest priority.
1.52 - template <typename _Item, typename _ItemIntMap, bool minimize = true >
1.53 - class LinearHeap {
1.54 -
1.55 - public:
1.56 - typedef _Item Item;
1.57 - typedef int Prio;
1.58 - typedef std::pair<Item, Prio> Pair;
1.59 - typedef _ItemIntMap ItemIntMap;
1.60 -
1.61 - /// \brief Type to represent the items states.
1.62 - ///
1.63 - /// Each Item element have a state associated to it. It may be "in heap",
1.64 - /// "pre heap" or "post heap". The latter two are indifferent from the
1.65 - /// heap's point of view, but may be useful to the user.
1.66 - ///
1.67 - /// The ItemIntMap \e should be initialized in such way that it maps
1.68 - /// PRE_HEAP (-1) to any element to be put in the heap...
1.69 - enum state_enum {
1.70 - IN_HEAP = 0,
1.71 - PRE_HEAP = -1,
1.72 - POST_HEAP = -2
1.73 - };
1.74 -
1.75 - public:
1.76 - /// \brief The constructor.
1.77 - ///
1.78 - /// The constructor.
1.79 - /// \param _index should be given to the constructor, since it is used
1.80 - /// internally to handle the cross references. The value of the map
1.81 - /// should be PRE_HEAP (-1) for each element.
1.82 - explicit LinearHeap(ItemIntMap &_index) : index(_index), minimal(0) {}
1.83 -
1.84 - /// The number of items stored in the heap.
1.85 - ///
1.86 - /// \brief Returns the number of items stored in the heap.
1.87 - int size() const { return data.size(); }
1.88 -
1.89 - /// \brief Checks if the heap stores no items.
1.90 - ///
1.91 - /// Returns \c true if and only if the heap stores no items.
1.92 - bool empty() const { return data.empty(); }
1.93 -
1.94 - /// \brief Make empty this heap.
1.95 - ///
1.96 - /// Make empty this heap.
1.97 - void clear() {
1.98 - for (int i = 0; i < (int)data.size(); ++i) {
1.99 - index[data[i].item] = -2;
1.100 - }
1.101 - data.clear(); first.clear(); minimal = 0;
1.102 - }
1.103 -
1.104 - private:
1.105 -
1.106 - void relocate_last(int idx) {
1.107 - if (idx + 1 < (int)data.size()) {
1.108 - data[idx] = data.back();
1.109 - if (data[idx].prev != -1) {
1.110 - data[data[idx].prev].next = idx;
1.111 - } else {
1.112 - first[data[idx].value] = idx;
1.113 - }
1.114 - if (data[idx].next != -1) {
1.115 - data[data[idx].next].prev = idx;
1.116 - }
1.117 - index[data[idx].item] = idx;
1.118 - }
1.119 - data.pop_back();
1.120 - }
1.121 -
1.122 - void unlace(int idx) {
1.123 - if (data[idx].prev != -1) {
1.124 - data[data[idx].prev].next = data[idx].next;
1.125 - } else {
1.126 - first[data[idx].value] = data[idx].next;
1.127 - }
1.128 - if (data[idx].next != -1) {
1.129 - data[data[idx].next].prev = data[idx].prev;
1.130 - }
1.131 - }
1.132 -
1.133 - void lace(int idx) {
1.134 - if ((int)first.size() <= data[idx].value) {
1.135 - first.resize(data[idx].value + 1, -1);
1.136 - }
1.137 - data[idx].next = first[data[idx].value];
1.138 - if (data[idx].next != -1) {
1.139 - data[data[idx].next].prev = idx;
1.140 - }
1.141 - first[data[idx].value] = idx;
1.142 - data[idx].prev = -1;
1.143 - }
1.144 -
1.145 - public:
1.146 - /// \brief Insert a pair of item and priority into the heap.
1.147 - ///
1.148 - /// Adds \c p.first to the heap with priority \c p.second.
1.149 - /// \param p The pair to insert.
1.150 - void push(const Pair& p) {
1.151 - push(p.first, p.second);
1.152 - }
1.153 -
1.154 - /// \brief Insert an item into the heap with the given priority.
1.155 - ///
1.156 - /// Adds \c i to the heap with priority \c p.
1.157 - /// \param i The item to insert.
1.158 - /// \param p The priority of the item.
1.159 - void push(const Item &i, const Prio &p) {
1.160 - int idx = data.size();
1.161 - index[i] = idx;
1.162 - data.push_back(LinearItem(i, p));
1.163 - lace(idx);
1.164 - if (p < minimal) {
1.165 - minimal = p;
1.166 - }
1.167 - }
1.168 -
1.169 - /// \brief Returns the item with minimum priority.
1.170 - ///
1.171 - /// This method returns the item with minimum priority.
1.172 - /// \pre The heap must be nonempty.
1.173 - Item top() const {
1.174 - while (first[minimal] == -1) {
1.175 - ++minimal;
1.176 - }
1.177 - return data[first[minimal]].item;
1.178 - }
1.179 -
1.180 - /// \brief Returns the minimum priority.
1.181 - ///
1.182 - /// It returns the minimum priority.
1.183 - /// \pre The heap must be nonempty.
1.184 - Prio prio() const {
1.185 - while (first[minimal] == -1) {
1.186 - ++minimal;
1.187 - }
1.188 - return minimal;
1.189 - }
1.190 -
1.191 - /// \brief Deletes the item with minimum priority.
1.192 - ///
1.193 - /// This method deletes the item with minimum priority from the heap.
1.194 - /// \pre The heap must be non-empty.
1.195 - void pop() {
1.196 - while (first[minimal] == -1) {
1.197 - ++minimal;
1.198 - }
1.199 - int idx = first[minimal];
1.200 - index[data[idx].item] = -2;
1.201 - unlace(idx);
1.202 - relocate_last(idx);
1.203 - }
1.204 -
1.205 - /// \brief Deletes \c i from the heap.
1.206 - ///
1.207 - /// This method deletes item \c i from the heap, if \c i was
1.208 - /// already stored in the heap.
1.209 - /// \param i The item to erase.
1.210 - void erase(const Item &i) {
1.211 - int idx = index[i];
1.212 - index[data[idx].item] = -2;
1.213 - unlace(idx);
1.214 - relocate_last(idx);
1.215 - }
1.216 -
1.217 -
1.218 - /// \brief Returns the priority of \c i.
1.219 - ///
1.220 - /// This function returns the priority of item \c i.
1.221 - /// \pre \c i must be in the heap.
1.222 - /// \param i The item.
1.223 - Prio operator[](const Item &i) const {
1.224 - int idx = index[i];
1.225 - return data[idx].value;
1.226 - }
1.227 -
1.228 - /// \brief \c i gets to the heap with priority \c p independently
1.229 - /// if \c i was already there.
1.230 - ///
1.231 - /// This method calls \ref push(\c i, \c p) if \c i is not stored
1.232 - /// in the heap and sets the priority of \c i to \c p otherwise.
1.233 - /// \param i The item.
1.234 - /// \param p The priority.
1.235 - void set(const Item &i, const Prio &p) {
1.236 - int idx = index[i];
1.237 - if (idx < 0) {
1.238 - push(i,p);
1.239 - } else if (p > data[idx].value) {
1.240 - increase(i, p);
1.241 - } else {
1.242 - decrease(i, p);
1.243 - }
1.244 - }
1.245 -
1.246 - /// \brief Decreases the priority of \c i to \c p.
1.247 -
1.248 - /// This method decreases the priority of item \c i to \c p.
1.249 - /// \pre \c i must be stored in the heap with priority at least \c
1.250 - /// p relative to \c Compare.
1.251 - /// \param i The item.
1.252 - /// \param p The priority.
1.253 - void decrease(const Item &i, const Prio &p) {
1.254 - int idx = index[i];
1.255 - unlace(idx);
1.256 - data[idx].value = p;
1.257 - if (p < minimal) {
1.258 - minimal = p;
1.259 - }
1.260 - lace(idx);
1.261 - }
1.262 -
1.263 - /// \brief Increases the priority of \c i to \c p.
1.264 - ///
1.265 - /// This method sets the priority of item \c i to \c p.
1.266 - /// \pre \c i must be stored in the heap with priority at most \c
1.267 - /// p relative to \c Compare.
1.268 - /// \param i The item.
1.269 - /// \param p The priority.
1.270 - void increase(const Item &i, const Prio &p) {
1.271 - int idx = index[i];
1.272 - unlace(idx);
1.273 - data[idx].value = p;
1.274 - lace(idx);
1.275 - }
1.276 -
1.277 - /// \brief Returns if \c item is in, has already been in, or has
1.278 - /// never been in the heap.
1.279 - ///
1.280 - /// This method returns PRE_HEAP if \c item has never been in the
1.281 - /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
1.282 - /// otherwise. In the latter case it is possible that \c item will
1.283 - /// get back to the heap again.
1.284 - /// \param i The item.
1.285 - state_enum state(const Item &i) const {
1.286 - int idx = index[i];
1.287 - if (idx >= 0) idx = 0;
1.288 - return state_enum(idx);
1.289 - }
1.290 -
1.291 - /// \brief Sets the state of the \c item in the heap.
1.292 - ///
1.293 - /// Sets the state of the \c item in the heap. It can be used to
1.294 - /// manually clear the heap when it is important to achive the
1.295 - /// better time complexity.
1.296 - /// \param i The item.
1.297 - /// \param st The state. It should not be \c IN_HEAP.
1.298 - void state(const Item& i, state_enum st) {
1.299 - switch (st) {
1.300 - case POST_HEAP:
1.301 - case PRE_HEAP:
1.302 - if (state(i) == IN_HEAP) {
1.303 - erase(i);
1.304 - }
1.305 - index[i] = st;
1.306 - break;
1.307 - case IN_HEAP:
1.308 - break;
1.309 - }
1.310 - }
1.311 -
1.312 - private:
1.313 -
1.314 - struct LinearItem {
1.315 - LinearItem(const Item& _item, int _value)
1.316 - : item(_item), value(_value) {}
1.317 -
1.318 - Item item;
1.319 - int value;
1.320 -
1.321 - int prev, next;
1.322 - };
1.323 -
1.324 - ItemIntMap& index;
1.325 - std::vector<int> first;
1.326 - std::vector<LinearItem> data;
1.327 - mutable int minimal;
1.328 -
1.329 - }; // class LinearHeap
1.330 -
1.331 -
1.332 - template <typename _Item, typename _ItemIntMap>
1.333 - class LinearHeap<_Item, _ItemIntMap, false> {
1.334 -
1.335 - public:
1.336 - typedef _Item Item;
1.337 - typedef int Prio;
1.338 - typedef std::pair<Item, Prio> Pair;
1.339 - typedef _ItemIntMap ItemIntMap;
1.340 -
1.341 - enum state_enum {
1.342 - IN_HEAP = 0,
1.343 - PRE_HEAP = -1,
1.344 - POST_HEAP = -2
1.345 - };
1.346 -
1.347 - public:
1.348 -
1.349 - explicit LinearHeap(ItemIntMap &_index) : index(_index), maximal(-1) {}
1.350 -
1.351 - int size() const { return data.size(); }
1.352 - bool empty() const { return data.empty(); }
1.353 -
1.354 - void clear() {
1.355 - for (int i = 0; i < (int)data.size(); ++i) {
1.356 - index[data[i].item] = -2;
1.357 - }
1.358 - data.clear(); first.clear(); maximal = -1;
1.359 - }
1.360 -
1.361 - private:
1.362 -
1.363 - void relocate_last(int idx) {
1.364 - if (idx + 1 != (int)data.size()) {
1.365 - data[idx] = data.back();
1.366 - if (data[idx].prev != -1) {
1.367 - data[data[idx].prev].next = idx;
1.368 - } else {
1.369 - first[data[idx].value] = idx;
1.370 - }
1.371 - if (data[idx].next != -1) {
1.372 - data[data[idx].next].prev = idx;
1.373 - }
1.374 - index[data[idx].item] = idx;
1.375 - }
1.376 - data.pop_back();
1.377 - }
1.378 -
1.379 - void unlace(int idx) {
1.380 - if (data[idx].prev != -1) {
1.381 - data[data[idx].prev].next = data[idx].next;
1.382 - } else {
1.383 - first[data[idx].value] = data[idx].next;
1.384 - }
1.385 - if (data[idx].next != -1) {
1.386 - data[data[idx].next].prev = data[idx].prev;
1.387 - }
1.388 - }
1.389 -
1.390 - void lace(int idx) {
1.391 - if ((int)first.size() <= data[idx].value) {
1.392 - first.resize(data[idx].value + 1, -1);
1.393 - }
1.394 - data[idx].next = first[data[idx].value];
1.395 - if (data[idx].next != -1) {
1.396 - data[data[idx].next].prev = idx;
1.397 - }
1.398 - first[data[idx].value] = idx;
1.399 - data[idx].prev = -1;
1.400 - }
1.401 -
1.402 - public:
1.403 -
1.404 - void push(const Pair& p) {
1.405 - push(p.first, p.second);
1.406 - }
1.407 -
1.408 - void push(const Item &i, const Prio &p) {
1.409 - int idx = data.size();
1.410 - index[i] = idx;
1.411 - data.push_back(LinearItem(i, p));
1.412 - lace(idx);
1.413 - if (data[idx].value > maximal) {
1.414 - maximal = data[idx].value;
1.415 - }
1.416 - }
1.417 -
1.418 - Item top() const {
1.419 - while (first[maximal] == -1) {
1.420 - --maximal;
1.421 - }
1.422 - return data[first[maximal]].item;
1.423 - }
1.424 -
1.425 - Prio prio() const {
1.426 - while (first[maximal] == -1) {
1.427 - --maximal;
1.428 - }
1.429 - return maximal;
1.430 - }
1.431 -
1.432 - void pop() {
1.433 - while (first[maximal] == -1) {
1.434 - --maximal;
1.435 - }
1.436 - int idx = first[maximal];
1.437 - index[data[idx].item] = -2;
1.438 - unlace(idx);
1.439 - relocate_last(idx);
1.440 - }
1.441 -
1.442 - void erase(const Item &i) {
1.443 - int idx = index[i];
1.444 - index[data[idx].item] = -2;
1.445 - unlace(idx);
1.446 - relocate_last(idx);
1.447 - }
1.448 -
1.449 - Prio operator[](const Item &i) const {
1.450 - int idx = index[i];
1.451 - return data[idx].value;
1.452 - }
1.453 -
1.454 - void set(const Item &i, const Prio &p) {
1.455 - int idx = index[i];
1.456 - if (idx < 0) {
1.457 - push(i,p);
1.458 - } else if (p > data[idx].value) {
1.459 - decrease(i, p);
1.460 - } else {
1.461 - increase(i, p);
1.462 - }
1.463 - }
1.464 -
1.465 - void decrease(const Item &i, const Prio &p) {
1.466 - int idx = index[i];
1.467 - unlace(idx);
1.468 - data[idx].value = p;
1.469 - if (p > maximal) {
1.470 - maximal = p;
1.471 - }
1.472 - lace(idx);
1.473 - }
1.474 -
1.475 - void increase(const Item &i, const Prio &p) {
1.476 - int idx = index[i];
1.477 - unlace(idx);
1.478 - data[idx].value = p;
1.479 - lace(idx);
1.480 - }
1.481 -
1.482 - state_enum state(const Item &i) const {
1.483 - int idx = index[i];
1.484 - if (idx >= 0) idx = 0;
1.485 - return state_enum(idx);
1.486 - }
1.487 -
1.488 - void state(const Item& i, state_enum st) {
1.489 - switch (st) {
1.490 - case POST_HEAP:
1.491 - case PRE_HEAP:
1.492 - if (state(i) == IN_HEAP) {
1.493 - erase(i);
1.494 - }
1.495 - index[i] = st;
1.496 - break;
1.497 - case IN_HEAP:
1.498 - break;
1.499 - }
1.500 - }
1.501 -
1.502 - private:
1.503 -
1.504 - struct LinearItem {
1.505 - LinearItem(const Item& _item, int _value)
1.506 - : item(_item), value(_value) {}
1.507 -
1.508 - Item item;
1.509 - int value;
1.510 -
1.511 - int prev, next;
1.512 - };
1.513 -
1.514 - ItemIntMap& index;
1.515 - std::vector<int> first;
1.516 - std::vector<LinearItem> data;
1.517 - mutable int maximal;
1.518 -
1.519 - }; // class LinearHeap
1.520 -
1.521 -}
1.522 -
1.523 -#endif