defmodule BoutiqueSuggestions do
def get_combinations(tops, bottoms, options \\ []) do
mp = Keyword.get(options, :maximum_price, 100.0)
for x <- tops,
y <- bottoms,
x.base_color != y.base_color and x.price + y.price <= mp do
{x, y}
end
end
end
Notes
Community Garden
|
Solution
Expand to see code (spoiler alert)
defmodule Plot do
@enforce_keys [:plot_id, :registered_to]
defstruct [:plot_id, :registered_to]
end
defmodule CommunityGarden do
@spec start(Keyword.t()) :: tuple()
def start(opts \\ []) do
Agent.start(fn -> [] end, opts)
end
@spec list_registrations(pid()) :: list(Plot)
def list_registrations(pid) do
Agent.get(pid, fn state -> state end)
end
@spec register(pid(), String.t()) :: Plot
def register(pid, register_to) do
Agent.update(pid, fn state ->
[%Plot{plot_id: get_next_id(state), registered_to: register_to} | state]
end)
Agent.get(pid, fn state ->
[head | _tail] = state
head
end)
end
defp get_next_id([]), do: 1
defp get_next_id(plots), do: Enum.sort_by(plots, & &1.plot_id)
@spec release(pid(), integer()) :: :ok
def release(pid, plot_id) do
Agent.update(pid, fn state ->
Enum.filter(state, fn plot -> plot.plot_id != plot_id end)
end)
end
@spec get_registration(pid(), integer()) :: tuple() | Plot
def get_registration(pid, plot_id) do
plot =
Agent.get(pid, fn state ->
Enum.find(state, nil, fn plot -> plot.plot_id == plot_id end)
end)
cond do
plot == nil -> {:not_found, "plot is unregistered"}
true -> plot
end
end
end
Notes
Bread and Potions
Solution
Expand to see code (spoiler alert)
defmodule RPG do
defmodule Character do
defstruct health: 100, mana: 0
end
defmodule LoafOfBread do
defstruct []
end
defmodule ManaPotion do
defstruct strength: 10
end
defmodule Poison do
defstruct []
end
defmodule EmptyBottle do
defstruct []
end
defprotocol Edible do
@spec eat(t(), %RPG.Character{}) :: any()
def eat(item, character)
end
defimpl Edible, for: LoafOfBread do
@spec eat(%RPG.LoafOfBread{}, %RPG.Character{}) :: {nil, %RPG.Character{}}
def eat(_item, character), do: {nil, %Character{character | health: character.health + 5}}
end
defimpl Edible, for: ManaPotion do
@spec eat(%RPG.ManaPotion{}, %RPG.Character{}) :: {%RPG.EmptyBottle{}, %RPG.Character{}}
def eat(item, character),
do: {%RPG.EmptyBottle{}, %Character{character | mana: character.mana + item.strength}}
end
defimpl Edible, for: Poison do
@spec eat(%RPG.Poison{}, %RPG.Character{}) :: {%RPG.EmptyBottle{}, %RPG.Character{}}
def eat(_item, character), do: {%RPG.EmptyBottle{}, %Character{character | health: 0}}
end
end
