BinHeap Class Template Reference
[Auxiliary Data Structures]

#include <lemon/bin_heap.h>

List of all members.


Detailed Description

template<typename Prio, typename ItemIntMap, typename Compare = std::less<Prio>>
class lemon::BinHeap< Prio, ItemIntMap, Compare >

This class implements the binary heap data structure. A heap is a data structure for storing items with specified values called priorities in such a way that finding the item with minimum priority is efficient. Compare specifies the ordering of the priorities. In a heap one can change the priority of an item, add or erase an item, etc.

Parameters:
Prio Type of the priority of the items.
ItemIntMap A read and writable Item int map, used internally to handle the cross references.
Compare A class for the ordering of the priorities. The default is std::less<Prio>.
See also:
FibHeap

Dijkstra


Public Types

enum  state_enum
 Type to represent the items states. More...

Public Member Functions

 BinHeap (ItemIntMap &_iim)
 The constructor.
 BinHeap (ItemIntMap &_iim, const Compare &_comp)
 The constructor.
int size () const
 Returns the number of items stored in the heap.
bool empty () const
 Checks if the heap stores no items.
void clear ()
 Make empty this heap.
void push (const PairType &p)
 Insert a pair of item and priority into the heap.
void push (const ItemType &i, const Prio &p)
 Insert an item into the heap with the given heap.
ItemType top () const
 Returns the item with minimum priority relative to Compare.
Prio prio () const
 Returns the minimum priority relative to Compare.
void pop ()
 Deletes the item with minimum priority relative to Compare.
void erase (const ItemType &i)
 Deletes i from the heap.
Prio operator[] (const ItemType &i) const
 Returns the priority of i.
void set (const ItemType &i, const Prio &p)
 i gets to the heap with priority p independently if i was already there.
void decrease (const ItemType &i, const Prio &p)
 Decreases the priority of i to p.
void increase (const ItemType &i, const Prio &p)
 Increases the priority of i to p.
state_enum state (const ItemType &i) const
 Returns if item is in, has already been in, or has never been in the heap.
void state (const ItemType &i, state_enum st)
 Sets the state of the item in the heap.


Member Enumeration Documentation

enum state_enum

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 should be initialized in such way that it maps PRE_HEAP (-1) to any element to be put in the heap...


Constructor & Destructor Documentation

BinHeap ( ItemIntMap &  _iim  )  [inline, explicit]

The constructor.

Parameters:
_iim 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.

BinHeap ( ItemIntMap &  _iim,
const Compare &  _comp 
) [inline]

The constructor.

Parameters:
_iim 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.
_comp The comparator function object.


Member Function Documentation

int size (  )  const [inline]

The number of items stored in the heap.

bool empty (  )  const [inline]

Returns true if and only if the heap stores no items.

void clear (  )  [inline]

Make empty this heap. It does not change the cross reference map. If you want to reuse what is not surely empty you should first clear the heap and after that you should set the cross reference map for each item to PRE_HEAP.

void push ( const PairType &  p  )  [inline]

Adds p.first to the heap with priority p.second.

Parameters:
p The pair to insert.

void push ( const ItemType &  i,
const Prio &  p 
) [inline]

Adds i to the heap with priority p.

Parameters:
i The item to insert.
p The priority of the item.

ItemType top (  )  const [inline]

This method returns the item with minimum priority relative to Compare.

Precondition:
The heap must be nonempty.

Prio prio (  )  const [inline]

It returns the minimum priority relative to Compare.

Precondition:
The heap must be nonempty.

void pop (  )  [inline]

This method deletes the item with minimum priority relative to Compare from the heap.

Precondition:
The heap must be non-empty.

void erase ( const ItemType &  i  )  [inline]

This method deletes item i from the heap, if i was already stored in the heap.

Parameters:
i The item to erase.

Prio operator[] ( const ItemType &  i  )  const [inline]

This function returns the priority of item i.

Precondition:
i must be in the heap.
Parameters:
i The item.

void set ( const ItemType &  i,
const Prio &  p 
) [inline]

This method calls push(i, p) if i is not stored in the heap and sets the priority of i to p otherwise.

Parameters:
i The item.
p The priority.

void decrease ( const ItemType &  i,
const Prio &  p 
) [inline]

This method decreases the priority of item i to p.

Precondition:
i must be stored in the heap with priority at least p relative to Compare.
Parameters:
i The item.
p The priority.

void increase ( const ItemType &  i,
const Prio &  p 
) [inline]

This method sets the priority of item i to p.

Precondition:
i must be stored in the heap with priority at most p relative to Compare.
Parameters:
i The item.
p The priority.

state_enum state ( const ItemType &  i  )  const [inline]

This method returns PRE_HEAP if 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 item will get back to the heap again.

Parameters:
i The item.

void state ( const ItemType &  i,
state_enum  st 
) [inline]

Sets the state of the item in the heap. It can be used to manually clear the heap when it is important to achive the better time complexity.

Parameters:
i The item.
st The state. It should not be IN_HEAP.


The documentation for this class was generated from the following file:
Generated on Tue Oct 31 09:49:49 2006 for LEMON by  doxygen 1.5.1