Red-black tree benchmark from Charlie's GoGaRuCo talk.

https://github.com/headius/gogaruco2012/blob/master/bench_red_black.rb

Author: BanzaiMan

bench/bench_red_black.rb

@@ -0,0 +1,361 @@
+require 'benchmark'
+
+# Algorithm based on "Introduction to Algorithms" by Cormen and others
+class RedBlackTree
+  class Node
+    attr_accessor :color
+    attr_accessor :key
+    attr_accessor :left
+    attr_accessor :right
+    attr_accessor :parent
+
+    RED = :red
+    BLACK = :black
+    COLORS = [RED, BLACK].freeze
+
+    def initialize(key, color = RED)
+      raise ArgumentError, "Bad value for color parameter" unless COLORS.include?(color)
+      @color = color
+      @key = key
+      @left = @right = @parent = NilNode.instance
+    end
+
+    def black?
+      return color == BLACK
+    end
+
+    def red?
+      return color == RED
+    end
+  end
+
+  class NilNode < Node
+    class << self
+      private :new
+
+      # it's not thread safe
+      def instance
+        @instance ||= begin
+          def instance
+            return @instance
+          end
+
+          new
+        end
+      end
+    end
+
+    def initialize
+      self.color = BLACK
+      self.key = 0
+      self.left = nil
+      self.right = nil
+      self.parent = nil
+    end
+
+    def nil?
+      return true
+    end
+  end
+
+  include Enumerable
+
+  attr_accessor :root
+  attr_accessor :size
+
+  def initialize
+    self.root = NilNode.instance
+    self.size = 0
+  end
+
+  def add(key)
+    insert(Node.new(key))
+  end
+
+  def insert(x)
+    insert_helper(x)
+
+    x.color = Node::RED
+    while x != root && x.parent.color == Node::RED
+      if x.parent == x.parent.parent.left
+        y = x.parent.parent.right
+        if !y.nil? && y.color == Node::RED
+          x.parent.color = Node::BLACK
+          y.color = Node::BLACK
+          x.parent.parent.color = Node::RED
+          x = x.parent.parent
+        else
+          if x == x.parent.right
+            x = x.parent
+            left_rotate(x)
+          end
+          x.parent.color = Node::BLACK
+          x.parent.parent.color = Node::RED
+          right_rotate(x.parent.parent)
+        end
+      else
+        y = x.parent.parent.left
+        if !y.nil? && y.color == Node::RED
+          x.parent.color = Node::BLACK
+          y.color = Node::BLACK
+          x.parent.parent.color = Node::RED
+          x = x.parent.parent
+        else
+          if x == x.parent.left
+            x = x.parent
+            right_rotate(x)
+          end
+          x.parent.color = Node::BLACK
+          x.parent.parent.color = Node::RED
+          left_rotate(x.parent.parent)
+        end
+      end
+    end
+    root.color = Node::BLACK
+  end
+
+  alias << insert
+
+  def delete(z)
+    y = (z.left.nil? || z.right.nil?) ? z : successor(z)
+    x = y.left.nil? ? y.right : y.left
+    x.parent = y.parent
+
+    if y.parent.nil?
+      self.root = x
+    else
+      if y == y.parent.left
+        y.parent.left = x
+      else
+        y.parent.right = x
+      end
+    end
+
+    z.key = y.key if y != z
+
+    if y.color == Node::BLACK
+      delete_fixup(x)
+    end
+
+    self.size -= 1
+    return y
+  end
+
+  def minimum(x = root)
+    while !x.left.nil?
+      x = x.left
+    end
+    return x
+  end
+
+  def maximum(x = root)
+    while !x.right.nil?
+      x = x.right
+    end
+    return x
+  end
+
+  def successor(x)
+    if !x.right.nil?
+      return minimum(x.right)
+    end
+    y = x.parent
+    while !y.nil? && x == y.right
+      x = y
+      y = y.parent
+    end
+    return y
+  end
+
+  def predecessor(x)
+    if !x.left.nil?
+      return maximum(x.left)
+    end
+    y = x.parent
+    while !y.nil? && x == y.left
+      x = y
+      y = y.parent
+    end
+    return y
+  end
+
+  def inorder_walk(x = root)
+    x = self.minimum
+    while !x.nil?
+      yield x.key
+      x = successor(x)
+    end
+  end
+
+  alias each inorder_walk
+
+  def reverse_inorder_walk(x = root)
+    x = self.maximum
+    while !x.nil?
+      yield x.key
+      x = predecessor(x)
+    end
+  end
+
+  alias reverse_each reverse_inorder_walk
+
+  def search(key, x = root)
+    while !x.nil? && x.key != key
+      key < x.key ? x = x.left : x = x.right
+    end
+    return x
+  end
+
+  def empty?
+    return self.root.nil?
+  end
+
+  def black_height(x = root)
+    height = 0
+    while !x.nil?
+      x = x.left
+      height +=1 if x.nil? || x.black?
+    end
+    return height
+  end
+
+private
+
+  def left_rotate(x)
+    raise "x.right is nil!" if x.right.nil?
+    y = x.right
+    x.right = y.left
+    y.left.parent = x if !y.left.nil?
+    y.parent = x.parent
+    if x.parent.nil?
+      self.root = y
+    else
+      if x == x.parent.left
+        x.parent.left = y
+      else
+        x.parent.right = y
+      end
+    end
+    y.left = x
+    x.parent = y
+  end
+
+  def right_rotate(x)
+    raise "x.left is nil!" if x.left.nil?
+    y = x.left
+    x.left = y.right
+    y.right.parent = x if !y.right.nil?
+    y.parent = x.parent
+    if x.parent.nil?
+      self.root = y
+    else
+      if x == x.parent.left
+        x.parent.left = y
+      else
+        x.parent.right = y
+      end
+    end
+    y.right = x
+    x.parent = y
+  end
+
+  def insert_helper(z)
+    y = NilNode.instance
+    x = root
+    while !x.nil?
+      y = x
+      z.key < x.key ? x = x.left : x = x.right
+    end
+    z.parent = y
+    if y.nil?
+      self.root = z
+    else
+      z.key < y.key ? y.left = z : y.right = z
+    end
+    self.size += 1
+  end
+
+  def delete_fixup(x)
+    while x != root && x.color == Node::BLACK
+      if x == x.parent.left
+        w = x.parent.right
+        if w.color == Node::RED
+          w.color = Node::BLACK
+          x.parent.color = Node::RED
+          left_rotate(x.parent)
+          w = x.parent.right
+        end
+        if w.left.color == Node::BLACK && w.right.color == Node::BLACK
+          w.color = Node::RED
+          x = x.parent
+        else
+          if w.right.color == Node::BLACK
+            w.left.color = Node::BLACK
+            w.color = Node::RED
+            right_rotate(w)
+            w = x.parent.right
+          end
+          w.color = x.parent.color
+          x.parent.color = Node::BLACK
+          w.right.color = Node::BLACK
+          left_rotate(x.parent)
+          x = root
+        end
+      else
+        w = x.parent.left
+        if w.color == Node::RED
+          w.color = Node::BLACK
+          x.parent.color = Node::RED
+          right_rotate(x.parent)
+          w = x.parent.left
+        end
+        if w.right.color == Node::BLACK && w.left.color == Node::BLACK
+          w.color = Node::RED
+          x = x.parent
+        else
+          if w.left.color == Node::BLACK
+            w.right.color = Node::BLACK
+            w.color = Node::RED
+            left_rotate(w)
+            w = x.parent.left
+          end
+          w.color = x.parent.color
+          x.parent.color = Node::BLACK
+          w.left.color = Node::BLACK
+          right_rotate(x.parent)
+          x = root
+        end
+      end
+    end
+    x.color = Node::BLACK
+  end
+end
+
+def rbt_bm
+  n = 100_000
+  a1 = []; n.times { a1 << rand(999_999) }
+  a2 = []; n.times { a2 << rand(999_999) }
+
+  start = Time.now
+
+  tree = RedBlackTree.new
+
+  n.times {|i| tree.add(i) }
+  n.times { tree.delete(tree.root) }
+
+  tree = RedBlackTree.new
+  a1.each {|e| tree.add(e) }
+  a2.each {|e| tree.search(e) }
+  tree.inorder_walk {|key| key + 1 }
+  tree.reverse_inorder_walk {|key| key + 1 }
+  n.times { tree.minimum }
+  n.times { tree.maximum }
+
+  return Time.now - start
+end
+
+N = (ARGV[0] || 10).to_i
+
+N.times do
+  puts rbt_bm.to_f
+end