Class: Containers::Queue
- Inherits:
-
Object
- Object
- Containers::Queue
- Includes:
- Enumerable
- Defined in:
- lib/containers/queue.rb
Overview
A Queue is a container that keeps elements in a first-in first-out (FIFO) order. Because of its
properties, it is often used as a buffer.
This implementation uses a doubly-linked list, guaranteeing O(1) complexity for all operations.
Instance Method Summary collapse
-
#each(&block) ⇒ Object
Iterate over the Queue in FIFO order.
-
#empty? ⇒ Boolean
Returns true if the queue is empty, false otherwise.
-
#initialize(ary = []) ⇒ Queue
constructor
Create a new queue.
-
#next ⇒ Object
Returns the next item from the queue but does not remove it.
-
#pop ⇒ Object
Removes the next item from the queue and returns it.
-
#push(obj) ⇒ Object
(also: #<<)
Adds an item to the queue.
-
#size ⇒ Object
Return the number of items in the queue.
Constructor Details
#initialize(ary = []) ⇒ Queue
Create a new queue. Takes an optional array argument to initialize the queue.
q = Containers::Queue.new([1, 2, 3])
q.pop #=> 1
q.pop #=> 2
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# File 'lib/containers/queue.rb', line 17 def initialize(ary=[]) @container = Containers::Deque.new(ary) end |
Instance Method Details
#each(&block) ⇒ Object
Iterate over the Queue in FIFO order.
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# File 'lib/containers/queue.rb', line 64 def each(&block) @container.each_forward(&block) end |
#empty? ⇒ Boolean
Returns true if the queue is empty, false otherwise.
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# File 'lib/containers/queue.rb', line 59 def empty? @container.empty? end |
#next ⇒ Object
Returns the next item from the queue but does not remove it.
q = Containers::Queue.new([1, 2, 3])
q.next #=> 1
q.size #=> 3
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# File 'lib/containers/queue.rb', line 26 def next @container.front end |
#pop ⇒ Object
Removes the next item from the queue and returns it.
q = Containers::Queue.new([1, 2, 3])
q.pop #=> 1
q.size #=> 2
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# File 'lib/containers/queue.rb', line 46 def pop @container.pop_front end |
#push(obj) ⇒ Object Also known as: <<
Adds an item to the queue.
q = Containers::Queue.new([1])
q.push(2)
q.pop #=> 1
q.pop #=> 2
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# File 'lib/containers/queue.rb', line 36 def push(obj) @container.push_back(obj) end |
#size ⇒ Object
Return the number of items in the queue.
q = Containers::Queue.new([1, 2, 3])
q.size #=> 3
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# File 'lib/containers/queue.rb', line 54 def size @container.size end |