deba@1724: /* -*- C++ -*-
deba@1724: *
alpar@1956: * This file is a part of LEMON, a generic C++ optimization library
alpar@1956: *
alpar@1956: * Copyright (C) 2003-2006
alpar@1956: * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@1724: * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@1724: *
deba@1724: * Permission to use, modify and distribute this software is granted
deba@1724: * provided that this copyright notice appears in all copies. For
deba@1724: * precise terms see the accompanying LICENSE file.
deba@1724: *
deba@1724: * This software is provided "AS IS" with no warranty of any kind,
deba@1724: * express or implied, and with no claim as to its suitability for any
deba@1724: * purpose.
deba@1724: *
deba@1724: */
deba@1724:
deba@1724: #ifndef LEMON_LINEAR_HEAP_H
deba@1724: #define LEMON_LINEAR_HEAP_H
deba@1724:
deba@1724: ///\ingroup auxdat
deba@1724: ///\file
deba@1724: ///\brief Binary Heap implementation.
deba@1724:
deba@1724: #include <vector>
deba@1724: #include <utility>
deba@1724: #include <functional>
deba@1724:
deba@1724: namespace lemon {
deba@1724:
deba@1834: /// \ingroup auxdat
deba@1724:
deba@1724: /// \brief A Linear Heap implementation.
deba@1724: ///
deba@1724: /// This class implements the \e linear \e heap data structure. A \e heap
deba@1724: /// is a data structure for storing items with specified values called \e
deba@1724: /// priorities in such a way that finding the item with minimum priority is
deba@1724: /// efficient. The linear heap is very simple implementation, it can store
deba@1724: /// only integer priorities and it stores for each priority in the [0..C]
deba@1724: /// range a list of items. So it should be used only when the priorities
deba@1724: /// are small. It is not intended to use as dijkstra heap.
deba@1724: ///
deba@1724: /// \param _Item Type of the items to be stored.
deba@1724: /// \param _ItemIntMap A read and writable Item int map, used internally
deba@1724: /// to handle the cross references.
deba@1724: /// \param minimize If the given parameter is true then the heap gives back
deba@1724: /// the lowest priority.
deba@1724: template <typename _Item, typename _ItemIntMap, bool minimize = true >
deba@1724: class LinearHeap {
deba@1724:
deba@1724: public:
deba@1724: typedef _Item Item;
deba@1724: typedef int Prio;
deba@1724: typedef std::pair<Item, Prio> Pair;
deba@1724: typedef _ItemIntMap ItemIntMap;
deba@1724:
deba@1724: /// \brief Type to represent the items states.
deba@1724: ///
deba@1724: /// Each Item element have a state associated to it. It may be "in heap",
deba@1724: /// "pre heap" or "post heap". The latter two are indifferent from the
deba@1724: /// heap's point of view, but may be useful to the user.
deba@1724: ///
deba@1724: /// The ItemIntMap \e should be initialized in such way that it maps
deba@1724: /// PRE_HEAP (-1) to any element to be put in the heap...
deba@1724: enum state_enum {
deba@1724: IN_HEAP = 0,
deba@1724: PRE_HEAP = -1,
deba@1724: POST_HEAP = -2
deba@1724: };
deba@1724:
deba@1724: public:
deba@1724: /// \brief The constructor.
deba@1724: ///
deba@1724: /// The constructor.
deba@1724: /// \param _index should be given to the constructor, since it is used
deba@1724: /// internally to handle the cross references. The value of the map
deba@1724: /// should be PRE_HEAP (-1) for each element.
deba@1724: explicit LinearHeap(ItemIntMap &_index) : index(_index), minimal(0) {}
deba@1724:
deba@1724: /// The number of items stored in the heap.
deba@1724: ///
deba@1724: /// \brief Returns the number of items stored in the heap.
deba@1724: int size() const { return data.size(); }
deba@1724:
deba@1724: /// \brief Checks if the heap stores no items.
deba@1724: ///
deba@1724: /// Returns \c true if and only if the heap stores no items.
deba@1724: bool empty() const { return data.empty(); }
deba@1724:
deba@1724: /// \brief Make empty this heap.
deba@1724: ///
deba@1724: /// Make empty this heap.
deba@1724: void clear() {
deba@1724: for (int i = 0; i < (int)data.size(); ++i) {
deba@1724: index[data[i].item] = -2;
deba@1724: }
deba@1724: data.clear(); first.clear(); minimal = 0;
deba@1724: }
deba@1724:
deba@1724: private:
deba@1724:
deba@1724: void relocate_last(int idx) {
deba@1724: if (idx + 1 < (int)data.size()) {
deba@1724: data[idx] = data.back();
deba@1724: if (data[idx].prev != -1) {
deba@1724: data[data[idx].prev].next = idx;
deba@1724: } else {
deba@1724: first[data[idx].value] = idx;
deba@1724: }
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = idx;
deba@1724: }
deba@1724: index[data[idx].item] = idx;
deba@1724: }
deba@1724: data.pop_back();
deba@1724: }
deba@1724:
deba@1724: void unlace(int idx) {
deba@1724: if (data[idx].prev != -1) {
deba@1724: data[data[idx].prev].next = data[idx].next;
deba@1724: } else {
deba@1724: first[data[idx].value] = data[idx].next;
deba@1724: }
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = data[idx].prev;
deba@1724: }
deba@1724: }
deba@1724:
deba@1724: void lace(int idx) {
deba@1724: if ((int)first.size() <= data[idx].value) {
deba@1724: first.resize(data[idx].value + 1, -1);
deba@1724: }
deba@1724: data[idx].next = first[data[idx].value];
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = idx;
deba@1724: }
deba@1724: first[data[idx].value] = idx;
deba@1724: data[idx].prev = -1;
deba@1724: }
deba@1724:
deba@1724: public:
deba@1724: /// \brief Insert a pair of item and priority into the heap.
deba@1724: ///
deba@1724: /// Adds \c p.first to the heap with priority \c p.second.
deba@1724: /// \param p The pair to insert.
deba@1724: void push(const Pair& p) {
deba@1724: push(p.first, p.second);
deba@1724: }
deba@1724:
deba@1724: /// \brief Insert an item into the heap with the given priority.
deba@1724: ///
deba@1724: /// Adds \c i to the heap with priority \c p.
deba@1724: /// \param i The item to insert.
deba@1724: /// \param p The priority of the item.
deba@1724: void push(const Item &i, const Prio &p) {
deba@1724: int idx = data.size();
deba@1724: index[i] = idx;
deba@1724: data.push_back(LinearItem(i, p));
deba@1724: lace(idx);
deba@1724: if (p < minimal) {
deba@1724: minimal = p;
deba@1724: }
deba@1724: }
deba@1724:
deba@1758: /// \brief Returns the item with minimum priority.
deba@1724: ///
deba@1758: /// This method returns the item with minimum priority.
deba@1724: /// \pre The heap must be nonempty.
deba@1724: Item top() const {
deba@1724: while (first[minimal] == -1) {
deba@1724: ++minimal;
deba@1724: }
deba@1724: return data[first[minimal]].item;
deba@1724: }
deba@1724:
deba@1758: /// \brief Returns the minimum priority.
deba@1724: ///
deba@1758: /// It returns the minimum priority.
deba@1724: /// \pre The heap must be nonempty.
deba@1724: Prio prio() const {
deba@1724: while (first[minimal] == -1) {
deba@1724: ++minimal;
deba@1724: }
deba@1724: return minimal;
deba@1724: }
deba@1724:
deba@1758: /// \brief Deletes the item with minimum priority.
deba@1724: ///
deba@1758: /// This method deletes the item with minimum priority from the heap.
deba@1724: /// \pre The heap must be non-empty.
deba@1724: void pop() {
deba@1724: while (first[minimal] == -1) {
deba@1724: ++minimal;
deba@1724: }
deba@1724: int idx = first[minimal];
deba@1724: index[data[idx].item] = -2;
deba@1724: unlace(idx);
deba@1724: relocate_last(idx);
deba@1724: }
deba@1724:
deba@1724: /// \brief Deletes \c i from the heap.
deba@1724: ///
deba@1724: /// This method deletes item \c i from the heap, if \c i was
deba@1724: /// already stored in the heap.
deba@1724: /// \param i The item to erase.
deba@1724: void erase(const Item &i) {
deba@1724: int idx = index[i];
deba@1724: index[data[idx].item] = -2;
deba@1724: unlace(idx);
deba@1724: relocate_last(idx);
deba@1724: }
deba@1724:
deba@1724:
deba@1724: /// \brief Returns the priority of \c i.
deba@1724: ///
deba@1724: /// This function returns the priority of item \c i.
deba@1724: /// \pre \c i must be in the heap.
deba@1724: /// \param i The item.
deba@1724: Prio operator[](const Item &i) const {
deba@1724: int idx = index[i];
deba@1724: return data[idx].value;
deba@1724: }
deba@1724:
deba@1724: /// \brief \c i gets to the heap with priority \c p independently
deba@1724: /// if \c i was already there.
deba@1724: ///
deba@1724: /// This method calls \ref push(\c i, \c p) if \c i is not stored
deba@1724: /// in the heap and sets the priority of \c i to \c p otherwise.
deba@1724: /// \param i The item.
deba@1724: /// \param p The priority.
deba@1724: void set(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: if (idx < 0) {
deba@1724: push(i,p);
deba@1724: } else if (p > data[idx].value) {
deba@1724: increase(i, p);
deba@1724: } else {
deba@1724: decrease(i, p);
deba@1724: }
deba@1724: }
deba@1724:
deba@1724: /// \brief Decreases the priority of \c i to \c p.
deba@1724:
deba@1724: /// This method decreases the priority of item \c i to \c p.
deba@1724: /// \pre \c i must be stored in the heap with priority at least \c
deba@1724: /// p relative to \c Compare.
deba@1724: /// \param i The item.
deba@1724: /// \param p The priority.
deba@1724: void decrease(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: unlace(idx);
deba@1724: data[idx].value = p;
deba@1724: if (p < minimal) {
deba@1724: minimal = p;
deba@1724: }
deba@1724: lace(idx);
deba@1724: }
deba@1724:
deba@1724: /// \brief Increases the priority of \c i to \c p.
deba@1724: ///
deba@1724: /// This method sets the priority of item \c i to \c p.
deba@1724: /// \pre \c i must be stored in the heap with priority at most \c
deba@1724: /// p relative to \c Compare.
deba@1724: /// \param i The item.
deba@1724: /// \param p The priority.
deba@1724: void increase(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: unlace(idx);
deba@1724: data[idx].value = p;
deba@1724: lace(idx);
deba@1724: }
deba@1724:
deba@1724: /// \brief Returns if \c item is in, has already been in, or has
deba@1724: /// never been in the heap.
deba@1724: ///
deba@1724: /// This method returns PRE_HEAP if \c item has never been in the
deba@1724: /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
deba@1724: /// otherwise. In the latter case it is possible that \c item will
deba@1724: /// get back to the heap again.
deba@1724: /// \param i The item.
deba@1724: state_enum state(const Item &i) const {
deba@1724: int idx = index[i];
deba@1724: if (idx >= 0) idx = 0;
deba@1724: return state_enum(idx);
deba@1724: }
deba@1724:
deba@1902: /// \brief Sets the state of the \c item in the heap.
deba@1902: ///
deba@1902: /// Sets the state of the \c item in the heap. It can be used to
deba@1902: /// manually clear the heap when it is important to achive the
deba@1902: /// better time complexity.
deba@1902: /// \param i The item.
deba@1902: /// \param st The state. It should not be \c IN_HEAP.
deba@1902: void state(const Item& i, state_enum st) {
deba@1902: switch (st) {
deba@1902: case POST_HEAP:
deba@1902: case PRE_HEAP:
deba@1902: if (state(i) == IN_HEAP) {
deba@1902: erase(i);
deba@1902: }
deba@1902: index[i] = st;
deba@1902: break;
deba@1906: case IN_HEAP:
deba@1906: break;
deba@1902: }
deba@1902: }
deba@1902:
deba@1724: private:
deba@1724:
deba@1724: struct LinearItem {
deba@1724: LinearItem(const Item& _item, int _value)
deba@1724: : item(_item), value(_value) {}
deba@1724:
deba@1724: Item item;
deba@1724: int value;
deba@1724:
deba@1724: int prev, next;
deba@1724: };
deba@1724:
deba@1724: ItemIntMap& index;
deba@1724: std::vector<int> first;
deba@1724: std::vector<LinearItem> data;
deba@1724: mutable int minimal;
deba@1724:
deba@1724: }; // class LinearHeap
deba@1724:
deba@1724:
deba@1724: template <typename _Item, typename _ItemIntMap>
deba@1724: class LinearHeap<_Item, _ItemIntMap, false> {
deba@1724:
deba@1724: public:
deba@1724: typedef _Item Item;
deba@1724: typedef int Prio;
deba@1724: typedef std::pair<Item, Prio> Pair;
deba@1724: typedef _ItemIntMap ItemIntMap;
deba@1724:
deba@1724: enum state_enum {
deba@1724: IN_HEAP = 0,
deba@1724: PRE_HEAP = -1,
deba@1724: POST_HEAP = -2
deba@1724: };
deba@1724:
deba@1724: public:
deba@1724:
deba@1724: explicit LinearHeap(ItemIntMap &_index) : index(_index), maximal(-1) {}
deba@1724:
deba@1724: int size() const { return data.size(); }
deba@1724: bool empty() const { return data.empty(); }
deba@1724:
deba@1724: void clear() {
deba@1724: for (int i = 0; i < (int)data.size(); ++i) {
deba@1724: index[data[i].item] = -2;
deba@1724: }
deba@1724: data.clear(); first.clear(); maximal = -1;
deba@1724: }
deba@1724:
deba@1724: private:
deba@1724:
deba@1724: void relocate_last(int idx) {
deba@1724: if (idx + 1 != (int)data.size()) {
deba@1724: data[idx] = data.back();
deba@1724: if (data[idx].prev != -1) {
deba@1724: data[data[idx].prev].next = idx;
deba@1724: } else {
deba@1724: first[data[idx].value] = idx;
deba@1724: }
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = idx;
deba@1724: }
deba@1724: index[data[idx].item] = idx;
deba@1724: }
deba@1724: data.pop_back();
deba@1724: }
deba@1724:
deba@1724: void unlace(int idx) {
deba@1724: if (data[idx].prev != -1) {
deba@1724: data[data[idx].prev].next = data[idx].next;
deba@1724: } else {
deba@1724: first[data[idx].value] = data[idx].next;
deba@1724: }
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = data[idx].prev;
deba@1724: }
deba@1724: }
deba@1724:
deba@1724: void lace(int idx) {
deba@1724: if ((int)first.size() <= data[idx].value) {
deba@1724: first.resize(data[idx].value + 1, -1);
deba@1724: }
deba@1724: data[idx].next = first[data[idx].value];
deba@1724: if (data[idx].next != -1) {
deba@1724: data[data[idx].next].prev = idx;
deba@1724: }
deba@1724: first[data[idx].value] = idx;
deba@1724: data[idx].prev = -1;
deba@1724: }
deba@1724:
deba@1724: public:
deba@1724:
deba@1724: void push(const Pair& p) {
deba@1724: push(p.first, p.second);
deba@1724: }
deba@1724:
deba@1724: void push(const Item &i, const Prio &p) {
deba@1724: int idx = data.size();
deba@1724: index[i] = idx;
deba@1724: data.push_back(LinearItem(i, p));
deba@1724: lace(idx);
deba@1724: if (data[idx].value > maximal) {
deba@1724: maximal = data[idx].value;
deba@1724: }
deba@1724: }
deba@1724:
deba@1724: Item top() const {
deba@1724: while (first[maximal] == -1) {
deba@1724: --maximal;
deba@1724: }
deba@1724: return data[first[maximal]].item;
deba@1724: }
deba@1724:
deba@1724: Prio prio() const {
deba@1724: while (first[maximal] == -1) {
deba@1724: --maximal;
deba@1724: }
deba@1724: return maximal;
deba@1724: }
deba@1724:
deba@1724: void pop() {
deba@1724: while (first[maximal] == -1) {
deba@1724: --maximal;
deba@1724: }
deba@1724: int idx = first[maximal];
deba@1724: index[data[idx].item] = -2;
deba@1724: unlace(idx);
deba@1724: relocate_last(idx);
deba@1724: }
deba@1724:
deba@1724: void erase(const Item &i) {
deba@1724: int idx = index[i];
deba@1724: index[data[idx].item] = -2;
deba@1724: unlace(idx);
deba@1724: relocate_last(idx);
deba@1724: }
deba@1724:
deba@1724: Prio operator[](const Item &i) const {
deba@1724: int idx = index[i];
deba@1724: return data[idx].value;
deba@1724: }
deba@1724:
deba@1724: void set(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: if (idx < 0) {
deba@1724: push(i,p);
deba@1724: } else if (p > data[idx].value) {
deba@1724: decrease(i, p);
deba@1724: } else {
deba@1724: increase(i, p);
deba@1724: }
deba@1724: }
deba@1724:
deba@1724: void decrease(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: unlace(idx);
deba@1724: data[idx].value = p;
deba@1724: if (p > maximal) {
deba@1724: maximal = p;
deba@1724: }
deba@1724: lace(idx);
deba@1724: }
deba@1724:
deba@1724: void increase(const Item &i, const Prio &p) {
deba@1724: int idx = index[i];
deba@1724: unlace(idx);
deba@1724: data[idx].value = p;
deba@1724: lace(idx);
deba@1724: }
deba@1724:
deba@1724: state_enum state(const Item &i) const {
deba@1724: int idx = index[i];
deba@1724: if (idx >= 0) idx = 0;
deba@1724: return state_enum(idx);
deba@1724: }
deba@1724:
deba@1902: void state(const Item& i, state_enum st) {
deba@1902: switch (st) {
deba@1902: case POST_HEAP:
deba@1902: case PRE_HEAP:
deba@1902: if (state(i) == IN_HEAP) {
deba@1902: erase(i);
deba@1902: }
deba@1902: index[i] = st;
deba@1902: break;
deba@1906: case IN_HEAP:
deba@1906: break;
deba@1902: }
deba@1902: }
deba@1902:
deba@1724: private:
deba@1724:
deba@1724: struct LinearItem {
deba@1724: LinearItem(const Item& _item, int _value)
deba@1724: : item(_item), value(_value) {}
deba@1724:
deba@1724: Item item;
deba@1724: int value;
deba@1724:
deba@1724: int prev, next;
deba@1724: };
deba@1724:
deba@1724: ItemIntMap& index;
deba@1724: std::vector<int> first;
deba@1724: std::vector<LinearItem> data;
deba@1724: mutable int maximal;
deba@1724:
deba@1724: }; // class LinearHeap
deba@1724:
deba@1724: }
deba@1724:
deba@1724: #endif