seanhandley

def left_of?(set_a, val_a, set_b, val_b)
  (0..4).any? do |i|
    set_a[i]   == val_a &&
    set_b[i+1] == val_b
  end
end

# Instead of defining a right_of?, we can just swap the values we input to left_of?

def next_to?(set_a, val_a, set_b, val_b)

seanhandley

def left_of?(set_a, val_a, set_b, val_b)
  (0..4).any? do |i|
    set_a[i]   == val_a &&
    set_b[i+1] == val_b
  end
end

colors = [:white, :yellow, :blue, :red, :green]

left_of?(colors, :green, colors, :white)

seanhandley

implies?(nationalities, :british, colors, :red)
implies?(nationalities, :swedish, pets, :dogs) 
implies?(colors, :green, drinks, :coffee)
implies?(nationalities, :danish, drinks, :tea)
implies?(cigars, :pall_mall, pets, :birds)
implies?(nationalities , :german, cigars, :prince)
implies?(colors, :yellow, cigars, :dunhill)
implies?(cigars, :bluemasters,  drinks, :beer)

seanhandley

def implies?(set_a, val_a, set_b, val_b)
  (0..4).any? do |i|
    set_a[i] == val_a &&
    set_b[i] == val_b
  end
end

# The German lives in the third house (position 2)
nationalities = [:swedish, :british,   :german, :norwegian,   :danish]
# The third house' occupant smokes Prince (position 2)

seanhandley

colors = [:white, :yellow, :blue, :red, :green]
# House 1 => white
# House 2 => yellow
# House 3 => blue
# House 4 => red
# House 5 => green

seanhandley

[:white, :yellow, :blue, :red, :green].permutation.each do |colors|
  [:german, :swedish, :british, :norwegian, :danish,].permutation.each do |nationalities|
    [:birds, :cats, :horses, :fish, :dogs].permutation.each do |pets|       
      [:beer, :water, :tea, :milk, :coffee].permutation.each do |drinks|
        [:blends, :pall_mall, :prince, :bluemasters, :dunhill].permutation.each do |cigars|
          # ...
        end
      end
    end
  end

seanhandley

colors = [:white, :yellow, :blue, :red, :green].permutation
# => #<Enumerator: [:white, :yellow, :blue, :red, :green]:permutation>

colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[0]
# => [:white, :yellow, :blue, :red, :green]

colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[1]
# => [:white, :yellow, :blue, :green, :red]
colors = [:white, :yellow, :blue, :red, :green].permutation.to_a[2]
# => [:white, :yellow, :red, :blue, :green]

seanhandley

Keybase proof

I hereby claim:

• I am seanhandley on github.
• I am seanhandley (https://keybase.io/seanhandley) on keybase.
• I have a public key whose fingerprint is 9685 2CA9 5B02 1A6F 9DB4 73FC 42C5 9834 59D4 0286

To claim this, I am signing this object:

seanhandley

# There are five houses in five different colors in a row.
# In each house lives a person with a different nationality.
# The five owners drink a certain type of beverage,
# smoke a certain brand of cigar and keep a certain pet.
# No owners have the same pet, smoke the same brand of cigar,
# or drink the same beverage.

# The question is: who owns the fish?

time_start = Time.now

seanhandley

# ...
deb http://nginx.org/packages/mainline/ubuntu/ trusty nginx
deb-src http://nginx.org/packages/mainline/ubuntu/ trusty nginx

# Where 'trusty' is the Ubuntu release codename (see `cat /etc/lsb-release`)