The Deque class
(Информация о версии неизвестна, возможно, только в SVN)
Введение
A Deque (pronounced “deck”) is a sequence of values in a contiguous buffer that grows and shrinks automatically. The name is a common abbreviation of “double-ended queue” and is used internally by Ds\Queue.
Two pointers are used to keep track of a head and a tail. The pointers can “wrap around” the end of the buffer, which avoids the need to move other values around to make room. This makes shift and unshift very fast — something a Ds\Vector can’t compete with.
Accessing a value by index requires a translation between the index and its
corresponding position in the buffer: ((head + position) % capacity).
Strengths
- Supports array syntax (square brackets).
- Uses less overall memory than an array for the same number of values.
- Automatically frees allocated memory when its size drops low enough.
- get(), set(), push(), pop(), shift(), and unshift() are all O(1).
Weaknesses
- Capacity must be a power of 2.
- insert() and remove() are O(n).
Обзор классов
Ds\Deque
implements
Ds\Sequence
{
/* Constants */
/* Методы */
}Предопределенные константы
Ds\Deque::MIN_CAPACITY
Содержание
- Ds\Deque::allocate — Allocates enough memory for a required capacity.
- Ds\Deque::apply — Updates all values by applying a callback function to each value.
- Ds\Deque::capacity — Returns the current capacity.
- Ds\Deque::clear — Removes all values from the deque.
- Ds\Deque::__construct — Creates a new instance.
- Ds\Deque::contains — Determines if the deque contains given values.
- Ds\Deque::copy — Returns a shallow copy of the deque.
- Ds\Deque::count — Returns the number of values in the collection.
- Ds\Deque::filter — Creates a new deque using a callable to determine which values to include.
- Ds\Deque::find — Attempts to find a value's index.
- Ds\Deque::first — Returns the first value in the deque.
- Ds\Deque::get — Returns the value at a given index.
- Ds\Deque::insert — Inserts values at a given index.
- Ds\Deque::isEmpty — Returns whether the deque is empty
- Ds\Deque::join — Joins all values together as a string.
- Ds\Deque::jsonSerialize — Returns a representation that can be converted to JSON.
- Ds\Deque::last — Returns the last value.
- Ds\Deque::map — Returns the result of applying a callback to each value.
- Ds\Deque::merge — Returns the result of adding all given values to the deque.
- Ds\Deque::pop — Removes and returns the last value.
- Ds\Deque::push — Adds values to the end of the deque.
- Ds\Deque::reduce — Reduces the deque to a single value using a callback function.
- Ds\Deque::remove — Removes and returns a value by index.
- Ds\Deque::reverse — Reverses the deque in-place.
- Ds\Deque::reversed — Returns a reversed copy.
- Ds\Deque::rotate — Rotates the deque by a given number of rotations.
- Ds\Deque::set — Updates a value at a given index.
- Ds\Deque::shift — Removes and returns the first value.
- Ds\Deque::slice — Returns a sub-deque of a given range.
- Ds\Deque::sort — Sorts the deque in-place.
- Ds\Deque::sorted — Returns a sorted copy.
- Ds\Deque::sum — Returns the sum of all values in the deque.
- Ds\Deque::toArray — Converts the deque to an array.
- Ds\Deque::unshift — Adds values to the front of the deque.
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