Class: DSA::BasicBinarySearchTree

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/DSA/binary_search_tree.rb

Overview

A basic binary search tree(or ordered map), with no specific self balancing

Direct Known Subclasses

RedBlackTree

Instance Method Summary collapse

Constructor Details

#initialize ⇒ BasicBinarySearchTree

Returns a new instance of BasicBinarySearchTree.



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# File 'lib/DSA/binary_search_tree.rb', line 18

def initialize
  @root = nil
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 38

def [](key)
  return nil if @root.nil?
  node = find_node @root, key
  if node
    node.value
  else
    nil
  end
end

#[]=(key, value) ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 22

def []=(key, value)
  new_node = BasicBinarySearchTreeNode.new(key, value)
  if @root.nil?
    @root = new_node
  else
    insert(@root, new_node)
  end
end

#bfs_print ⇒ Object

breadth first traversal



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# File 'lib/DSA/binary_search_tree.rb', line 190

def bfs_print
  puts '=' * 100
  level = [@root]
  until level.empty?
    next_level = []
    level.each do |node|
      if node
        printf "<#{node.key}, #{node.value}>"
        printf "(parent_is_#{node.parent.key})\t" if node != @root
        next_level.push node.left
        next_level.push node.right
      else
        printf "<Nil>\t"
        next_level.push nil
        next_level.push nil
      end
    end
    puts
    if next_level.count(nil) < next_level.length
      level = next_level
    else
      level = []
    end
  end
  puts '=' * 100
end

#delete(key) ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 31

def delete(key)
  return nil if @root.nil?
  node = find_node @root, key
  return nil if node.nil?
  delete_node(node).first.value
end

#each ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 160

def each
  return if @root.nil?
  if block_given?
    in_order_traversal @root, Proc.new
  else
    Enumerator.new do |y|
      each do |key, value|
        y << [key, value]
      end
    end
  end
end

#ge(key) ⇒ Object

yield the key/value pair for all those great than or equal to input key



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# File 'lib/DSA/binary_search_tree.rb', line 103

def ge(key)
  return nil if @root.nil?

  if block_given?
    node = find_node @root, key
    yield [node.key, node.value] if node
    node = find_gt_node @root, key
    if node
      yield [node.key, node.value]
      loop do
        node = in_order_next_node node
        if node
          yield [node.key, node.value]
        else
          break
        end
      end
    end
  else
    Enumerator.new do |y|
      ge(key) do |key, value|
        y << [key, value]
      end
    end
  end
end

#gt(key) ⇒ Object

yield the key/value pair for all those great than input key



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# File 'lib/DSA/binary_search_tree.rb', line 49

def gt(key)
  return nil if @root.nil?

  if block_given?
    node = find_gt_node @root, key
    if node
      yield [node.key, node.value]
      loop do
        node = in_order_next_node node
        if node
          yield [node.key, node.value]
        else
          break
        end
      end
    end
  else
    Enumerator.new do |y|
      gt(key) do |key, value|
        y << [key, value]
      end
    end
  end


end

#le(key) ⇒ Object

yield the key/value pair for all those great than or equal to input key



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# File 'lib/DSA/binary_search_tree.rb', line 131

def le(key)
  return nil if @root.nil?

  if block_given?
    node = find_node @root, key
    yield [node.key, node.value] if node
    node = find_lt_node @root, key
    if node
      yield [node.key, node.value]
      loop do
        node = in_order_prev_node node
        if node
          yield [node.key, node.value]
        else
          break
        end
      end
    end
  else
    Enumerator.new do |y|
      le(key) do |key, value|
        y << [key, value]
      end
    end
  end

end

#lt(key) ⇒ Object

yield the key/value pair for all those less than input key



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# File 'lib/DSA/binary_search_tree.rb', line 77

def lt(key)
  return nil if @root.nil?

  if block_given?
    node = find_lt_node @root, key
    if node
      yield [node.key, node.value]
      loop do
        node = in_order_prev_node node
        if node
          yield [node.key, node.value]
        else
          break
        end
      end
    end
  else
    Enumerator.new do |y|
      lt(key) do |key, value|
        y << [key, value]
      end
    end
  end
end

#max ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 181

def max
  if @root.nil?
    nil
  else
    max_node(@root).value
  end
end

#min ⇒ Object 



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# File 'lib/DSA/binary_search_tree.rb', line 173

def min
  if @root.nil?
    nil
  else
    min_node(@root).value
  end
end