Data commit

Task/Prime-conspiracy/Elixir/prime-conspiracy.elixir

@@ -0,0 +1,27 @@
+defmodule Prime do
+  def conspiracy(m) do
+    IO.puts "#{m} first primes. Transitions prime % 10 → next-prime % 10."
+    Enum.map(prime(m), &rem(&1, 10))
+    |> Enum.chunk(2,1)
+    |> Enum.reduce(Map.new, fn [a,b],acc -> Map.update(acc, {a,b}, 1, &(&1+1)) end)
+    |> Enum.sort
+    |> Enum.each(fn {{a,b},v} ->
+         sv = to_string(v) |> String.rjust(10)
+         sf = Float.to_string(100.0*v/m, [decimals: 4])
+         IO.puts "#{a} → #{b} count:#{sv} frequency:#{sf} %"
+       end)
+  end
+
+  def prime(n) do
+    max = n * :math.log(n * :math.log(n)) |> trunc      # from Rosser's theorem
+    Enum.to_list(2..max)
+    |> prime(:math.sqrt(max), [])
+    |> Enum.take(n)
+  end
+  defp prime([h|t], limit, result) when h>limit, do: Enum.reverse(result, [h|t])
+  defp prime([h|t], limit, result) do
+    prime((for x <- t, rem(x,h)>0, do: x), limit, [h|result])
+  end
+end
+
+Prime.conspiracy(1000000)