Created
April 22, 2016 21:47
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#version 1 | |
class Deque | |
def initialize | |
@head = nil | |
@tail = nil | |
end | |
def push(data) | |
if @head.nil? | |
@head = Node.new(data) | |
@tail = @head | |
else | |
current_node = @head | |
until current_node.next_node == nil | |
current_node = current_node.next_node | |
end | |
current_node.next_node = Node.new(data, current_node) | |
@tail = current_node.next_node | |
end | |
end | |
def pop | |
data = @tail.data | |
if @tail == @head | |
@head = nil | |
@tail = nil | |
else | |
@tail = @tail.previous_node | |
@tail.next_node = nil | |
end | |
data | |
end | |
def shift | |
data = @head.data | |
if @tail == @head | |
@head = nil | |
@tail = nil | |
else | |
@head = @head.next_node | |
@head.previous_node = nil | |
end | |
data | |
end | |
def unshift(data) | |
if @head.nil? | |
@head = Node.new(data) | |
@tail = @head | |
@head.data | |
else | |
@head.previous_node = Node.new(data, nil, @head) | |
@head = @head.previous_node | |
end | |
end | |
end | |
class Node | |
attr_accessor :data, :next_node, :previous_node | |
def initialize(data, previous_node = nil, next_node = nil) | |
@data = data | |
@next_node = next_node | |
@previous_node = previous_node | |
end | |
end | |
#version 2 | |
class Deque | |
def initialize | |
@head = nil | |
end | |
def node_step_push(head, data) | |
current_node = head | |
until current_node.next_node == nil | |
current_node = current_node.next_node | |
end | |
current_node.next_node = Node.new(data, current_node) | |
end | |
def node_step_pop(head) | |
current_node = head | |
until current_node.next_node.next_node == nil | |
current_node = current_node.next_node | |
end | |
data = current_node.next_node.data | |
current_node.next_node = nil | |
data | |
end | |
def push(data) | |
if @head.nil? | |
@head = Node.new(data) | |
else | |
node_step_push(@head, data) | |
end | |
end | |
def pop | |
if @head.next_node.nil? | |
data = @head.data | |
@head = nil | |
else | |
data = node_step_pop(@head) | |
end | |
data | |
end | |
def shift | |
data = @head.data | |
if @head.next_node.nil? | |
@head = nil | |
else | |
@head = @head.next_node | |
@head.previous_node = nil | |
end | |
data | |
end | |
def unshift(data) | |
if @head.nil? | |
@head = Node.new(data) | |
@head.data | |
else | |
@head.previous_node = Node.new(data, nil, @head) | |
@head = @head.previous_node | |
end | |
end | |
end | |
class Node | |
attr_accessor :data, :next_node, :previous_node | |
def initialize(data, previous_node = nil, next_node = nil) | |
@data = data | |
@next_node = next_node | |
@previous_node = previous_node | |
end | |
end |
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