priority_queue - CTL - C Container Template library

Defined in header <ctl/priority_queue.h>, CTL prefix pqu, derived from vector.

SYNOPSIS

static inline int
int_cmp(int *a, int *b) {
  return *a < *b;
}

#define POD
#define T int
#include <ctl/priority_queue.h>

pqu_int a = pqu_int_init (int_cmp);

for (i=0; i<1000; i++)
  pqu_int_push(&a, rand());
for (i=0; i<20; i++)
   pqu_int_pop(&a);

pqu_int_free(&a);

DESCRIPTION

A priority queue is a container adaptor that provides constant time lookup of the largest (by default) element, at the expense of logarithmic insertion and extraction.

The function names are composed of the prefix pqu_, the user-defined type T and the method name. E.g pqu_int with #define T int.

A user-provided Compare can be supplied to change the ordering, e.g. using greater would cause the smallest element to appear as the top().

Working with a priority_queue is similar to managing a heap in some random access container, with the benefit of not being able to accidentally invalidate the heap.

Member types

T value type

A being pqu_T container type

I being pqu_T_it iterator type (hidden)

There is no B node type.

Member functions

A init (int T_compare(T*,T*))

constructs the priority_queue.

free (A* self)

destructs the priority_queue.

A copy (A* self)

returns a copy of the container.

Element access

T* top (A* self)

access the first element

Capacity

int empty (A* self)

checks whether the container is empty

size_t size (A* self)

returns the number of elements

size_t max_size ()

returns the maximum possible number of elements, hard-coded to 2GB (32bit).

size_t capacity (A* self)

returns the number of elements that can be held in currently allocated storage

Modifiers

push (A* self, T value)

inserts the element

emplace (A* self, T* value)

constructs elements in-place. (C++11)

pop (A* self)

removes the top element

swap (A* self, A* other)

swaps the contents of both containers.

No algorithm applicable, as we have no iterators.