Heap< Prio, ItemIntMap > Class Template Reference
[Concepts]

---

Detailed Description

template<typename Prio, typename ItemIntMap>
class lemon::concepts::Heap< Prio, ItemIntMap >

A concept structure describes the main interface of heaps. #include <lemon/concepts/heap.h>

List of all members.

Public Types
enum	State
	Type to represent the items states. More...
typedef ItemIntMap::Key	Item
	Type of the items stored in the heap.
Public Member Functions
	Heap (ItemIntMap &_iim)
	The constructor.
int	size () const
	The number of items stored in the heap.
bool	empty () const
	Checks if the heap stores no items.
void	clear ()
	Makes empty this heap.
void	push (const Item &i, const Prio &p)
	Insert an item into the heap with the given heap.
Item	top () const
	Returns the item with minimum priority.
Prio	prio () const
	Returns the minimum priority.
void	pop ()
	Deletes the item with minimum priority.
void	erase (const Item &i)
	Deletes i from the heap.
Prio	operator[] (const Item &i) const
	Returns the priority of i.
void	set (const Item &i, const Prio &p)
	i gets to the heap with priority p independently if i was already there.
void	decrease (const Item &i, const Prio &p)
	Decreases the priority of i to p.
void	increase (const Item &i, const Prio &p)
	Increases the priority of i to p.
State	state (const Item &i) const
	Returns if item is in, has already been in, or has never been in the heap.
void	state (const Item &i, State st)
	Sets the state of the item in the heap.

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Member Enumeration Documentation

enum State

Each Item element have a state associated to it. It may be "in heap", "pre heap" or "post heap". The later 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...

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Constructor & Destructor Documentation

Heap

(

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.

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Member Function Documentation

int size

(

)

const [inline]

Returns 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

(

)

Makes this heap empty.

void push	(	const Item &	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.

Item top

(

)

const [inline]

This method returns the item with minimum priority.

Precondition:

The heap must be nonempty.

Prio prio

(

)

const [inline]

It returns the minimum priority.

Precondition:

The heap must be nonempty.

void pop

(

)

[inline]

This method deletes the item with minimum priority.

Precondition:

The heap must be non-empty.

void erase

(

const Item &

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 Item &

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 Item &	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. It may throw an UnderFlowPriorityException.

Parameters:

	i	The item.
	p	The priority.

void decrease	(	const Item &	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.

Parameters:

	i	The item.
	p	The priority.

void increase	(	const Item &	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 state

(

const Item &

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 Item &	i,
		State	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.