diff -r fb4f801dd692 -r b20777184ba8 lemon/linear_heap.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lemon/linear_heap.h	Fri Oct 14 10:58:54 2005 +0000
@@ -0,0 +1,486 @@
+/* -*- C++ -*-
+ * lemon/linear_heap.h - Part of LEMON, a generic C++ optimization library
+ *
+ * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
+ * (Egervary Research Group on Combinatorial Optimization, EGRES).
+ *
+ * Permission to use, modify and distribute this software is granted
+ * provided that this copyright notice appears in all copies. For
+ * precise terms see the accompanying LICENSE file.
+ *
+ * This software is provided "AS IS" with no warranty of any kind,
+ * express or implied, and with no claim as to its suitability for any
+ * purpose.
+ *
+ */
+
+#ifndef LEMON_LINEAR_HEAP_H
+#define LEMON_LINEAR_HEAP_H
+
+///\ingroup auxdat
+///\file
+///\brief Binary Heap implementation.
+
+#include <vector>
+#include <utility>
+#include <functional>
+
+namespace lemon {
+
+  /// \addtogroup auxdat
+  /// @{
+
+  /// \brief A Linear Heap implementation.
+  ///
+  /// This class implements the \e linear \e heap data structure. A \e heap
+  /// is a data structure for storing items with specified values called \e
+  /// priorities in such a way that finding the item with minimum priority is
+  /// efficient. The linear heap is very simple implementation, it can store
+  /// only integer priorities and it stores for each priority in the [0..C]
+  /// range a list of items. So it should be used only when the priorities
+  /// are small. It is not intended to use as dijkstra heap.
+  ///
+  /// \param _Item Type of the items to be stored.  
+  /// \param _ItemIntMap A read and writable Item int map, used internally
+  /// to handle the cross references.
+  /// \param minimize If the given parameter is true then the heap gives back
+  /// the lowest priority. 
+  template <typename _Item, typename _ItemIntMap, bool minimize = true >
+  class LinearHeap {
+
+  public:
+    typedef _Item Item;
+    typedef int Prio;
+    typedef std::pair<Item, Prio> Pair;
+    typedef _ItemIntMap ItemIntMap;
+
+    /// \brief Type to represent the items states.
+    ///
+    /// Each Item element have a state associated to it. It may be "in heap",
+    /// "pre heap" or "post heap". The latter two are indifferent from the
+    /// heap's point of view, but may be useful to the user.
+    ///
+    /// The ItemIntMap \e should be initialized in such way that it maps
+    /// PRE_HEAP (-1) to any element to be put in the heap...
+    enum state_enum {
+      IN_HEAP = 0,
+      PRE_HEAP = -1,
+      POST_HEAP = -2
+    };
+
+  public:
+    /// \brief The constructor.
+    ///
+    /// The constructor.
+    /// \param _index should be given to the constructor, since it is used
+    /// internally to handle the cross references. The value of the map
+    /// should be PRE_HEAP (-1) for each element.
+    explicit LinearHeap(ItemIntMap &_index) : index(_index), minimal(0) {}
+    
+    /// The number of items stored in the heap.
+    ///
+    /// \brief Returns the number of items stored in the heap.
+    int size() const { return data.size(); }
+    
+    /// \brief Checks if the heap stores no items.
+    ///
+    /// Returns \c true if and only if the heap stores no items.
+    bool empty() const { return data.empty(); }
+
+    /// \brief Make empty this heap.
+    /// 
+    /// Make empty this heap.
+    void clear() { 
+      for (int i = 0; i < (int)data.size(); ++i) {
+	index[data[i].item] = -2;
+      }
+      data.clear(); first.clear(); minimal = 0;
+    }
+
+  private:
+
+    void relocate_last(int idx) {
+      if (idx + 1 < (int)data.size()) {
+	data[idx] = data.back();
+	if (data[idx].prev != -1) {
+	  data[data[idx].prev].next = idx;
+	} else {
+	  first[data[idx].value] = idx;
+	}
+	if (data[idx].next != -1) {
+	  data[data[idx].next].prev = idx;
+	}
+	index[data[idx].item] = idx;
+      }
+      data.pop_back();
+    }
+
+    void unlace(int idx) {
+      if (data[idx].prev != -1) {
+	data[data[idx].prev].next = data[idx].next;
+      } else {
+	first[data[idx].value] = data[idx].next;
+      }
+      if (data[idx].next != -1) {
+	data[data[idx].next].prev = data[idx].prev;
+      }
+    }
+
+    void lace(int idx) {
+      if ((int)first.size() <= data[idx].value) {
+	first.resize(data[idx].value + 1, -1);
+      }
+      data[idx].next = first[data[idx].value];
+      if (data[idx].next != -1) {
+	data[data[idx].next].prev = idx;
+      }
+      first[data[idx].value] = idx;
+      data[idx].prev = -1;
+    }
+
+  public:
+    /// \brief Insert a pair of item and priority into the heap.
+    ///
+    /// Adds \c p.first to the heap with priority \c p.second.
+    /// \param p The pair to insert.
+    void push(const Pair& p) {
+      push(p.first, p.second);
+    }
+
+    /// \brief Insert an item into the heap with the given priority.
+    ///    
+    /// Adds \c i to the heap with priority \c p. 
+    /// \param i The item to insert.
+    /// \param p The priority of the item.
+    void push(const Item &i, const Prio &p) { 
+      int idx = data.size();
+      index[i] = idx;
+      data.push_back(LinearItem(i, p));
+      lace(idx);
+      if (p < minimal) {
+	minimal = p;
+      }
+    }
+
+    /// \brief Returns the item with minimum priority relative to \c Compare.
+    ///
+    /// This method returns the item with minimum priority relative to \c
+    /// Compare.  
+    /// \pre The heap must be nonempty.  
+    Item top() const {
+      while (first[minimal] == -1) {
+	++minimal;
+      }
+      return data[first[minimal]].item;
+    }
+
+    /// \brief Returns the minimum priority relative to \c Compare.
+    ///
+    /// It returns the minimum priority relative to \c Compare.
+    /// \pre The heap must be nonempty.
+    Prio prio() const {
+      while (first[minimal] == -1) {
+	++minimal;
+      }
+      return minimal;
+    }
+
+    /// \brief Deletes the item with minimum priority relative to \c Compare.
+    ///
+    /// This method deletes the item with minimum priority relative to \c
+    /// Compare from the heap.  
+    /// \pre The heap must be non-empty.  
+    void pop() {
+      while (first[minimal] == -1) {
+	++minimal;
+      }
+      int idx = first[minimal];
+      index[data[idx].item] = -2;
+      unlace(idx);
+      relocate_last(idx);
+    }
+
+    /// \brief Deletes \c i from the heap.
+    ///
+    /// This method deletes item \c i from the heap, if \c i was
+    /// already stored in the heap.
+    /// \param i The item to erase. 
+    void erase(const Item &i) {
+      int idx = index[i];
+      index[data[idx].item] = -2;
+      unlace(idx);
+      relocate_last(idx);
+    }
+
+    
+    /// \brief Returns the priority of \c i.
+    ///
+    /// This function returns the priority of item \c i.  
+    /// \pre \c i must be in the heap.
+    /// \param i The item.
+    Prio operator[](const Item &i) const {
+      int idx = index[i];
+      return data[idx].value;
+    }
+
+    /// \brief \c i gets to the heap with priority \c p independently 
+    /// if \c i was already there.
+    ///
+    /// This method calls \ref push(\c i, \c p) if \c i is not stored
+    /// in the heap and sets the priority of \c i to \c p otherwise.
+    /// \param i The item.
+    /// \param p The priority.
+    void set(const Item &i, const Prio &p) {
+      int idx = index[i];
+      if (idx < 0) {
+	push(i,p);
+      } else if (p > data[idx].value) {
+	increase(i, p);
+      } else {
+	decrease(i, p);
+      }
+    }
+
+    /// \brief Decreases the priority of \c i to \c p.
+
+    /// This method decreases the priority of item \c i to \c p.
+    /// \pre \c i must be stored in the heap with priority at least \c
+    /// p relative to \c Compare.
+    /// \param i The item.
+    /// \param p The priority.
+    void decrease(const Item &i, const Prio &p) {
+      int idx = index[i];
+      unlace(idx);
+      data[idx].value = p;
+      if (p < minimal) {
+	minimal = p;
+      }
+      lace(idx);
+    }
+    
+    /// \brief Increases the priority of \c i to \c p.
+    ///
+    /// This method sets the priority of item \c i to \c p. 
+    /// \pre \c i must be stored in the heap with priority at most \c
+    /// p relative to \c Compare.
+    /// \param i The item.
+    /// \param p The priority.
+    void increase(const Item &i, const Prio &p) {
+      int idx = index[i];
+      unlace(idx);
+      data[idx].value = p;
+      lace(idx);
+    }
+
+    /// \brief Returns if \c item is in, has already been in, or has 
+    /// never been in the heap.
+    ///
+    /// This method returns PRE_HEAP if \c item has never been in the
+    /// heap, IN_HEAP if it is in the heap at the moment, and POST_HEAP
+    /// otherwise. In the latter case it is possible that \c item will
+    /// get back to the heap again.
+    /// \param i The item.
+    state_enum state(const Item &i) const {
+      int idx = index[i];
+      if (idx >= 0) idx = 0;
+      return state_enum(idx);
+    }
+
+  private:
+
+    struct LinearItem {
+      LinearItem(const Item& _item, int _value) 
+	: item(_item), value(_value) {}
+
+      Item item;
+      int value;
+
+      int prev, next;
+    };
+
+    ItemIntMap& index;
+    std::vector<int> first;
+    std::vector<LinearItem> data;
+    mutable int minimal;
+
+  }; // class LinearHeap
+
+
+  template <typename _Item, typename _ItemIntMap>
+  class LinearHeap<_Item, _ItemIntMap, false> {
+
+  public:
+    typedef _Item Item;
+    typedef int Prio;
+    typedef std::pair<Item, Prio> Pair;
+    typedef _ItemIntMap ItemIntMap;
+
+    enum state_enum {
+      IN_HEAP = 0,
+      PRE_HEAP = -1,
+      POST_HEAP = -2
+    };
+
+  public:
+
+    explicit LinearHeap(ItemIntMap &_index) : index(_index), maximal(-1) {}
+
+    int size() const { return data.size(); }
+    bool empty() const { return data.empty(); }
+
+    void clear() { 
+      for (int i = 0; i < (int)data.size(); ++i) {
+	index[data[i].item] = -2;
+      }
+      data.clear(); first.clear(); maximal = -1; 
+    }
+
+  private:
+
+    void relocate_last(int idx) {
+      if (idx + 1 != (int)data.size()) {
+	data[idx] = data.back();
+	if (data[idx].prev != -1) {
+	  data[data[idx].prev].next = idx;
+	} else {
+	  first[data[idx].value] = idx;
+	}
+	if (data[idx].next != -1) {
+	  data[data[idx].next].prev = idx;
+	}
+	index[data[idx].item] = idx;
+      }
+      data.pop_back();
+    }
+
+    void unlace(int idx) {
+      if (data[idx].prev != -1) {
+	data[data[idx].prev].next = data[idx].next;
+      } else {
+	first[data[idx].value] = data[idx].next;
+      }
+      if (data[idx].next != -1) {
+	data[data[idx].next].prev = data[idx].prev;
+      }
+    }
+
+    void lace(int idx) {
+      if ((int)first.size() <= data[idx].value) {
+	first.resize(data[idx].value + 1, -1);
+      }
+      data[idx].next = first[data[idx].value];
+      if (data[idx].next != -1) {
+	data[data[idx].next].prev = idx;
+      }
+      first[data[idx].value] = idx;
+      data[idx].prev = -1;
+    }
+
+  public:
+
+    void push(const Pair& p) {
+      push(p.first, p.second);
+    }
+
+    void push(const Item &i, const Prio &p) { 
+      int idx = data.size();
+      index[i] = idx;
+      data.push_back(LinearItem(i, p));
+      lace(idx);
+      if (data[idx].value > maximal) {
+	maximal = data[idx].value;
+      }
+    }
+
+    Item top() const {
+      while (first[maximal] == -1) {
+	--maximal;
+      }
+      return data[first[maximal]].item;
+    }
+
+    Prio prio() const {
+      while (first[maximal] == -1) {
+	--maximal;
+      }
+      return maximal;
+    }
+
+    void pop() {
+      while (first[maximal] == -1) {
+	--maximal;
+      }
+      int idx = first[maximal];
+      index[data[idx].item] = -2;
+      unlace(idx);
+      relocate_last(idx);
+    }
+
+    void erase(const Item &i) {
+      int idx = index[i];
+      index[data[idx].item] = -2;
+      unlace(idx);
+      relocate_last(idx);
+    }
+
+    Prio operator[](const Item &i) const {
+      int idx = index[i];
+      return data[idx].value;
+    }
+
+    void set(const Item &i, const Prio &p) {
+      int idx = index[i];
+      if (idx < 0) {
+	push(i,p);
+      } else if (p > data[idx].value) {
+	decrease(i, p);
+      } else {
+	increase(i, p);
+      }
+    }
+
+    void decrease(const Item &i, const Prio &p) {
+      int idx = index[i];
+      unlace(idx);
+      data[idx].value = p;
+      if (p > maximal) {
+	maximal = p;
+      }
+      lace(idx);
+    }
+    
+    void increase(const Item &i, const Prio &p) {
+      int idx = index[i];
+      unlace(idx);
+      data[idx].value = p;
+      lace(idx);
+    }
+
+    state_enum state(const Item &i) const {
+      int idx = index[i];
+      if (idx >= 0) idx = 0;
+      return state_enum(idx);
+    }
+
+  private:
+
+    struct LinearItem {
+      LinearItem(const Item& _item, int _value) 
+	: item(_item), value(_value) {}
+
+      Item item;
+      int value;
+
+      int prev, next;
+    };
+
+    ItemIntMap& index;
+    std::vector<int> first;
+    std::vector<LinearItem> data;
+    mutable int maximal;
+
+  }; // class LinearHeap
+
+}
+  
+#endif