week1_hw_review.rb

# 1: Remove all hats. All are 0.
# 2: Every 2nd cat is switched to 1. [0, 1, 0, 1]
# 3: Every 3rd cat is switched (toggled). [0, 1, 1, 1]
# 4: [ 0, 1, 1, 0 ]

max = 100

cats = Array.new(max, 1)

p cats

def toggle cat
  if cat == 0
    1
  else
    0
  end
end

(1..max).each do |pass|
  cats.each_index do |index|
    remainder = (index + 1) % pass
    # puts "#{index + 1} has a remainder of #{remainder} when divided by #{pass}"
    if remainder == 0
      # print "Cat: "
      # p cats[index]
      cats[index] = toggle cats[index]
    end
  end
end

cats.each_with_index do |cat, index|
  puts "Cat #{index + 1} has no hat." if cat == 0
end


__END__

You have 100 cats in a row that are all wearing hats. You make 100 passes by the cats. The first time through, you visit every cat and remove its hat if it’s on, and put it on if it’s off. The second time you only visit every 2nd cat (cat #2, #4, #6, …). The third time, every 3rd cat (cat #3, #6, #9, …), etc, until you only visit the 100th cat.

After the last pass, which cats aren’t wearing hats?

Show the code you wrote to get this answer.
__END__
cat in the hat
pyramid