alexspark

class Node
  attr_accessor :value, :left, :right
  def initialize(value)
    @value = value
  end
end

def in_order_traversal(node)
  in_order_traversal node.left if node.left
  puts node.value

alexspark

class Node
  attr_accessor :value, :left, :right
  def initialize(value)
    @value = value
  end
end

def level_order_traversal(node)
  queue = [node]
  

alexspark

# This problem was asked by Google.
# 
# Given a stack of N elements, interleave the first half of the stack
# with the second half reversed using only one other queue. This should be done in-place.
# 
# Recall that you can only push or pop from a stack, and enqueue or dequeue from a queue.

def reverse_interleave(stack)
  return stack if stack.length < 3
  

alexspark

# This problem was asked by Uber.
# Given an array of integers, return a new array such that each element 
# at index i of the new array is the product of all the numbers in the original 
# array except the one at i. Solve it without using division and in O(n) time.
# For example, if our input was [1, 2, 3, 4, 5], the expected output would be [120, 60, 40, 30, 24].
# If our input was [3, 2, 1], the expected output would be [2, 3, 6].

def products_of_others(list)
  right_products = Array.new(list.length)
  left_products = Array.new(list.length)

alexspark

require 'benchmark'

module BenchmarkTest
  def self.find_pair_naive(list, sum)
    list.each_with_index do |first, index_1|
      list.each_with_index do |second, index_2|
        next if index_1.eql? index_2 
        
        if first + second == sum
          return [index_1, index_2]