Sha256: a0e048cc79128f8e54b769f777019201025433d1df0dee95cd2fa479ac786b50
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Size: 622 Bytes
Versions: 69
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Contents
defmodule PascalsTriangle do
@doc """
Calculates the rows of a pascal triangle
with the given height
"""
@spec rows(integer) :: [[integer]]
def rows(num) do
do_rows(num - 1, [[1]])
end
defp do_rows(0, rows), do: Enum.reverse(rows)
defp do_rows(n, rows = [h | _]) do
do_rows(n - 1, [next_row(h) | rows])
end
defp next_row(list) do
list
|> each_cons
|> Enum.map(fn [a, b] -> a + b end)
|> add_ends
end
defp each_cons(list) do
list
|> Enum.flat_map(&[&1, &1])
|> Enum.slice(1..-2)
|> Enum.chunk(2)
end
defp add_ends(list), do: [1] ++ list ++ [1]
end
Version data entries
69 entries across 69 versions & 1 rubygems