fl::priority_queue_stable< T, Compare > Class Template Reference

Detailed Description

template<typename T, typename Compare = fl::less<T>>
class fl::priority_queue_stable< T, Compare >

Stable priority queue that maintains FIFO ordering for equal-priority elements.

This is a wrapper around fl::PriorityQueue that adds a monotonic sequence counter to ensure stable (FIFO) ordering when elements have equal priority according to the comparison function.

Template Parameters:

• T: Element type (must be copyable)
• Compare: Comparison function (default: fl::less<T> for max-heap behavior)

By default, this creates a MAX-HEAP (largest element has highest priority). For custom types with special priority ordering, define operator< and use fl::greater<T>:

struct Task {
    int priority;
    bool operator<(const Task& o) const { return priority > o.priority; }  // Invert for max-heap
};
fl::priority_queue_stable<Task, fl::greater<Task>> queue;  // Use greater with inverted operator<

Example (default max-heap for integers):

fl::priority_queue_stable<int> queue;
queue.push(3);
queue.push(1);
queue.push(3);  // Same priority as first 3
// Pop order: 3 (first), 3 (second), 1 - FIFO for equal priorities

Definition at line 180 of file priority_queue.h.

#include <priority_queue.h>

Inheritance diagram for fl::priority_queue_stable< T, Compare >:

Collaboration diagram for fl::priority_queue_stable< T, Compare >:

Classes
struct	StableElement

Public Types
using	size_type = fl::size
using	value_type = T

Public Member Functions
	priority_queue_stable () FL_NOEXCEPT
void	clear ()
	Clear all elements from the queue.
template<typename... Args>
void	emplace (Args &&... args)
bool	empty () const
	Check if the queue is empty.
bool	operator!= (const priority_queue_stable &other) const
	Inequality comparison.
bool	operator< (const priority_queue_stable &other) const
	Lexicographic comparison.
bool	operator<= (const priority_queue_stable &other) const
	Less-than-or-equal comparison.
bool	operator== (const priority_queue_stable &other) const
	Equality comparison.
bool	operator> (const priority_queue_stable &other) const
	Greater-than comparison.
bool	operator>= (const priority_queue_stable &other) const
	Greater-than-or-equal comparison.
void	pop ()
	Remove the top element from the queue.
void	push (const T &value)
	Push an element into the priority queue.
fl::size	size () const
	Get the number of elements in the queue.
const T &	top () const
	Access the top element (highest priority)

Private Attributes
u64	mNextSequence
fl::PriorityQueue< StableElement >	mQueue

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The documentation for this class was generated from the following file:

• fl/stl/priority_queue.h