Checks if a binary tree's children all contain 2 nodes (except the last level.)

binary_tree_checker.rb

#!/usr/bin/env ruby
# encoding: utf-8

# Task: You are given number of nodes (n) in a binary tree.
#       You have to tell whether it is possible having a tree with given number of nodes
#       such that all nodes at all levels have 2 children (except the last level).

num_nodes = ARGV[0].to_i
total = 0
row = 0

while total < num_nodes
  total = total + (1 << row)
  row += 1
end

puts total == num_nodes ? 'Yes' : 'No'