Class template pairing

Class template pairing_heap

boost::heap::pairing_heap — pairing heap

Synopsis

// In header: <boost/heap/pairing_heap.hpp>

template<typename T, class... Options> 
class pairing_heap {
public:
  // types
  typedef T                                        value_type;      
  typedef implementation_defined::size_type        size_type;       
  typedef implementation_defined::difference_type  difference_type; 
  typedef implementation_defined::value_compare    value_compare;   
  typedef implementation_defined::allocator_type   allocator_type;  
  typedef implementation_defined::reference        reference;       
  typedef implementation_defined::const_reference  const_reference; 
  typedef implementation_defined::pointer          pointer;         
  typedef implementation_defined::const_pointer    const_pointer;   
  typedef implementation_defined::iterator         iterator;        
  typedef implementation_defined::const_iterator   const_iterator;  
  typedef implementation_defined::ordered_iterator ordered_iterator;
  typedef implementation_defined::handle_type      handle_type;     

  // construct/copy/destruct
  explicit pairing_heap(value_compare const & = value_compare());
  pairing_heap(pairing_heap const &);
  pairing_heap(pairing_heap &&);
  pairing_heap& operator=(pairing_heap &&);
  pairing_heap& operator=(pairing_heap const &);
  ~pairing_heap(void);

  // public member functions
  bool empty(void) const;
  size_type size(void) const;
  size_type max_size(void) const;
  void clear(void);
  allocator_type get_allocator(void) const;
  void swap(pairing_heap &);
  const_reference top(void) const;
  handle_type push(value_type const &);
  template<class... Args> handle_type emplace(Args &&...);
  void pop(void);
  void update(handle_type, const_reference);
  void update(handle_type);
  void increase(handle_type, const_reference);
  void increase(handle_type);
  void decrease(handle_type, const_reference);
  void decrease(handle_type);
  void erase(handle_type);
  iterator begin(void) const;
  iterator end(void) const;
  ordered_iterator ordered_begin(void) const;
  ordered_iterator ordered_end(void) const;
  void merge(pairing_heap &);
  value_compare const & value_comp(void) const;
  template<typename HeapType> bool operator<(HeapType const &) const;
  template<typename HeapType> bool operator>(HeapType const &) const;
  template<typename HeapType> bool operator>=(HeapType const &) const;
  template<typename HeapType> bool operator<=(HeapType const &) const;
  template<typename HeapType> bool operator==(HeapType const &) const;
  template<typename HeapType> bool operator!=(HeapType const &) const;

  // public static functions
  static handle_type s_handle_from_iterator(iterator const &);

  // public data members
  static const bool constant_time_size;
  static const bool has_ordered_iterators;
  static const bool is_mergable;
  static const bool is_stable;
  static const bool has_reserve;
};

Description

Pairing heaps are self-adjusting binary heaps. Although design and implementation are rather simple, the complexity analysis is yet unsolved. For details, consult:

Pettie, Seth (2005), "Towards a final analysis of pairing heaps", Proc. 46th Annual IEEE Symposium on Foundations of Computer Science, pp. 174–183

The template parameter T is the type to be managed by the container. The user can specify additional options and if no options are provided default options are used.

The container supports the following options:

boost::heap::compare<>, defaults to compare<std::less<T> >
boost::heap::stable<>, defaults to stable<false>
boost::heap::stability_counter_type<>, defaults to stability_counter_type<boost::uintmax_t>
boost::heap::allocator<>, defaults to allocator<std::allocator<T> >
boost::heap::constant_time_size<>, defaults to constant_time_size<true>

`pairing_heap` public types

typedef implementation_defined::iterator iterator;

Note: The iterator does not traverse the priority queue in order of the priorities.

`pairing_heap` public construct/copy/destruct

explicit pairing_heap(value_compare const & cmp = value_compare());

Effects: constructs an empty priority queue.

Complexity: Constant.

```
pairing_heap(pairing_heap const & rhs);
```
Effects: copy-constructs priority queue from rhs.

Complexity: Linear.
```
pairing_heap(pairing_heap && rhs);
```
Effects: C++11-style move constructor.

Complexity: Constant.

Note: Only available, if BOOST_HAS_RVALUE_REFS is defined
```
pairing_heap& operator=(pairing_heap && rhs);
```
Effects: C++11-style move assignment.

Complexity: Constant.

Note: Only available, if BOOST_HAS_RVALUE_REFS is defined
```
pairing_heap& operator=(pairing_heap const & rhs);
```
Effects: Assigns priority queue from rhs.

Complexity: Linear.
```
~pairing_heap(void);
```

`pairing_heap` public member functions

```
bool empty(void) const;
```
Effects: Returns true, if the priority queue contains no elements.

Complexity: Constant.
```
size_type size(void) const;
```
Effects: Returns the number of elements contained in the priority queue.

Complexity: Constant, if configured with constant_time_size<true>, otherwise linear.
```
size_type max_size(void) const;
```
Effects: Returns the maximum number of elements the priority queue can contain.

Complexity: Constant.
```
void clear(void);
```
Effects: Removes all elements from the priority queue.

Complexity: Linear.
```
allocator_type get_allocator(void) const;
```
Effects: Returns allocator.

Complexity: Constant.
```
void swap(pairing_heap & rhs);
```
Effects: Swaps two priority queues.

Complexity: Constant.
```
const_reference top(void) const;
```
Effects: Returns a const_reference to the maximum element.

Complexity: Constant.
```
handle_type push(value_type const & v);
```
Effects: Adds a new element to the priority queue. Returns handle to element

Complexity: 2**2*log(log(N)) (amortized).
```
template<class... Args> handle_type emplace(Args &&... args);
```
Effects: Adds a new element to the priority queue. The element is directly constructed in-place. Returns handle to element.

Complexity: 2**2*log(log(N)) (amortized).
```
void pop(void);
```
Effects: Removes the top element from the priority queue.

Complexity: Logarithmic (amortized).
```
void update(handle_type handle, const_reference v);
```
Effects: Assigns v to the element handled by handle & updates the priority queue.

Complexity: 2**2*log(log(N)) (amortized).
```
void update(handle_type handle);
```
Effects: Updates the heap after the element handled by handle has been changed.

Complexity: 2**2*log(log(N)) (amortized).

Note: If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
```
void increase(handle_type handle, const_reference v);
```
Effects: Assigns v to the element handled by handle & updates the priority queue.

Complexity: 2**2*log(log(N)) (amortized).

Note: The new value is expected to be greater than the current one
```
void increase(handle_type handle);
```
Effects: Updates the heap after the element handled by handle has been changed.

Complexity: 2**2*log(log(N)) (amortized).

Note: If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
```
void decrease(handle_type handle, const_reference v);
```
Effects: Assigns v to the element handled by handle & updates the priority queue.

Complexity: 2**2*log(log(N)) (amortized).

Note: The new value is expected to be less than the current one
```
void decrease(handle_type handle);
```
Effects: Updates the heap after the element handled by handle has been changed.

Complexity: 2**2*log(log(N)) (amortized).

Note: The new value is expected to be less than the current one. If this is not called, after a handle has been updated, the behavior of the data structure is undefined!
```
void erase(handle_type handle);
```
Effects: Removes the element handled by handle from the priority_queue.

Complexity: 2**2*log(log(N)) (amortized).
```
iterator begin(void) const;
```
Effects: Returns an iterator to the first element contained in the priority queue.

Complexity: Constant.
```
iterator end(void) const;
```
Effects: Returns an iterator to the end of the priority queue.

Complexity: Constant.
```
ordered_iterator ordered_begin(void) const;
```
Effects: Returns an ordered iterator to the first element contained in the priority queue.

Note: Ordered iterators traverse the priority queue in heap order.
```
ordered_iterator ordered_end(void) const;
```
Effects: Returns an ordered iterator to the first element contained in the priority queue.

Note: Ordered iterators traverse the priority queue in heap order.
```
void merge(pairing_heap & rhs);
```
Effects: Merge all elements from rhs into this

Complexity: 2**2*log(log(N)) (amortized).
```
value_compare const & value_comp(void) const;
```
Effect: Returns the value_compare object used by the priority queue
```
template<typename HeapType> bool operator<(HeapType const & rhs) const;
```
Returns: Element-wise comparison of heap data structures

Requirement: the value_compare object of both heaps must match.
```
template<typename HeapType> bool operator>(HeapType const & rhs) const;
```
Returns: Element-wise comparison of heap data structures

Requirement: the value_compare object of both heaps must match.
```
template<typename HeapType> bool operator>=(HeapType const & rhs) const;
```
Returns: Element-wise comparison of heap data structures

Requirement: the value_compare object of both heaps must match.
```
template<typename HeapType> bool operator<=(HeapType const & rhs) const;
```
Returns: Element-wise comparison of heap data structures

Requirement: the value_compare object of both heaps must match.
```
template<typename HeapType> bool operator==(HeapType const & rhs) const;
```
Equivalent comparison Returns: True, if both heap data structures are equivalent.

Requirement: the value_compare object of both heaps must match.
```
template<typename HeapType> bool operator!=(HeapType const & rhs) const;
```
Equivalent comparison Returns: True, if both heap data structures are not equivalent.

Requirement: the value_compare object of both heaps must match.

`pairing_heap` public static functions

static handle_type s_handle_from_iterator(iterator const & it);