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class LinkedListNode | |
attr_accessor :value, :next_node | |
def initialize(value, next_node=nil) | |
@value = value | |
@next_node = next_node | |
end | |
end | |
def cycle_check(list_node) | |
tortoise_pointer = list_node | |
hare_pointer = list_node | |
while list_node | |
return false if hare_pointer.next_node.nil? | |
hare_pointer = hare_pointer.next_node | |
return false if hare_pointer.next_node.nil? | |
hare_pointer = hare_pointer.next_node | |
tortoise_pointer = tortoise_pointer.next_node | |
return true if hare_pointer == tortoise_pointer | |
end | |
false | |
end | |
infinite_node1 = LinkedListNode.new(37) | |
infinite_node2 = LinkedListNode.new(99, infinite_node1) | |
infinite_node3 = LinkedListNode.new(6, infinite_node2) | |
infinite_node4 = LinkedListNode.new(23, infinite_node3) | |
infinite_node5 = LinkedListNode.new(4, infinite_node4) | |
infinite_node6 = LinkedListNode.new(36, infinite_node5) | |
infinite_node1.next_node = infinite_node6 | |
puts "Infinity check on infinite list: #{cycle_check(infinite_node6)}" | |
puts "-------" | |
non_infinite_node1 = LinkedListNode.new(37) | |
non_infinite_node2 = LinkedListNode.new(99, non_infinite_node1) | |
non_infinite_node3 = LinkedListNode.new(12, non_infinite_node2) | |
non_infinite_node4 = LinkedListNode.new(55, non_infinite_node3) | |
puts "Infinity check on NON-infinite list: #{cycle_check(non_infinite_node3)}" |
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class LinkedListNode | |
attr_accessor :value, :next_node | |
def initialize(value, next_node=nil) | |
@value = value | |
@next_node = next_node | |
end | |
end | |
class Stack | |
attr_reader :data | |
def initialize | |
@data = nil | |
end | |
def push(element) | |
@data = LinkedListNode.new(element, @data) | |
end | |
def pop | |
old_data = @data | |
@data = @data.next_node | |
old_data | |
end | |
end | |
def print_values(list_node) | |
print "#{list_node.value} --> " | |
if list_node.next_node.nil? | |
print "nil\n" | |
return | |
else | |
print_values(list_node.next_node) | |
end | |
end | |
def reverse_list(list_node) | |
stack = Stack.new | |
while list_node | |
stack.push(list_node.value) | |
list_node = list_node.next_node | |
end | |
stack.pop | |
end | |
node1 = LinkedListNode.new(37) | |
node2 = LinkedListNode.new(99, node1) | |
node3 = LinkedListNode.new(12, node2) | |
print_values(node3) | |
puts "-------" | |
revlist = reverse_list(node3) | |
print_values(revlist) |
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class LinkedListNode | |
attr_accessor :value, :next_node | |
def initialize(value, next_node=nil) | |
@value = value | |
@next_node = next_node | |
end | |
end | |
def print_values(list_node) | |
print "#{list_node.value} --> " | |
if list_node.next_node.nil? | |
print "nil\n" | |
return | |
else | |
print_values(list_node.next_node) | |
end | |
end | |
def reverse_list(list_node, previous=nil) | |
next_node = list_node.next_node | |
list_node.next_node = previous | |
if next_node | |
reverse_list(next_node, list_node) | |
else | |
list_node | |
end | |
end | |
node1 = LinkedListNode.new(37) | |
node2 = LinkedListNode.new(99, node1) | |
node3 = LinkedListNode.new(12, node2) | |
print_values(node3) | |
puts "-------" | |
revlist = reverse_list(node3) | |
print_values(revlist) |
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