bird-count

elixir/bird-count/lib/bird_count.ex

@@ -0,0 +1,18 @@
+defmodule BirdCount do
+  def today([]), do: nil
+  def today([head | _tail]), do: head
+
+  def increment_day_count([]), do: [1]
+  def increment_day_count([head | tail]), do: [head + 1 | tail]
+
+  def has_day_without_birds?([]), do: false
+  def has_day_without_birds?([0 | _tail]), do: true
+  def has_day_without_birds?([_head | tail]), do: has_day_without_birds?(tail)
+
+  def total([]), do: 0
+  def total([head | tail]), do: head + total(tail)
+
+  def busy_days([]), do: 0
+  def busy_days([head | tail]) when head >= 5, do: 1 + busy_days(tail)
+  def busy_days([_head | tail]), do: busy_days(tail)
+end