Last active
January 4, 2016 00:39
-
-
Save genewoo/8542603 to your computer and use it in GitHub Desktop.
BST Implement in Ruby
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
class BSTree | |
attr_accessor :left, :right, :parent, :value | |
def initialize(value, parent = nil) | |
@value = value | |
@parent = parent | |
end | |
def self.build_by_array(array, parent = nil) | |
return nil unless array | |
if array.length == 1 | |
middle = 0 | |
else | |
middle = ((array.length - 1) * 1.0 / 2).floor | |
end | |
bst = BSTree.new(array[middle], parent) | |
# p "-" * 10 | |
# p middle | |
# p bst.value | |
# p "=" * 10 | |
if (middle > 0) | |
# p "L" | |
# p array[0..middle - 1] | |
bst.left = BSTree.build_by_array(array[0..middle - 1], parent) | |
end | |
if (middle < array.length - 1) | |
# p "R" | |
# p array[middle + 1 .. - 1] | |
bst.right = BSTree.build_by_array(array[middle + 1 .. - 1], parent) | |
end | |
bst | |
end | |
def to_nested_a | |
[@value, [@left.nil? ? nil : @left.to_nested_a, @right.nil? ? nil : @right.to_nested_a]] | |
end | |
def to_hash | |
hash = {} | |
hash.merge!({ left: @left.to_hash }) if @left | |
hash.merge!({ right: @right.to_hash }) if @right | |
{@value => hash} | |
end | |
def to_a | |
(@left.to_a + [@value] + @right.to_a).flatten | |
end | |
def validate? | |
(@left.nil? || @left.value < @value && @left.validate?) \ | |
&& (@right.nil? || @right.value > @value && @right.validate?) | |
end | |
def look_up(value) | |
if value == @value | |
return self | |
elsif value > @value | |
target = @right | |
else value < @value | |
target = @left | |
end | |
return target.look_up(value) if target | |
end | |
end | |
bst = BSTree.build_by_array((1..10).to_a) | |
puts bst.to_nested_a.inspect | |
puts bst.to_hash.inspect | |
puts bst.to_a == (1..10).to_a | |
puts bst.validate? | |
p bst.look_up(0) | |
p bst.look_up(10) | |
p bst.look_up(9) | |
p bst.look_up(1) | |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment