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Versions: 265
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Stored size: 1.39 KB
Contents
defmodule Minesweeper do
@doc """
Annotate empty spots next to mines with the number of mines next to them.
"""
@spec annotate([String.t]) :: [String.t]
def annotate([]), do: []
def annotate(board) do
h = length(board)
w = String.length(hd(board)) # Only 7-bit ASCII in the board, so this is safe
annotations =
Enum.reduce(Stream.with_index(board), %{}, fn { line, y }, acc ->
Enum.reduce(Stream.with_index(String.to_char_list(line)), acc, fn
{ ?*, x }, acc -> add_adjacents(acc, { x, y }, { w, h })
_, acc -> acc
end)
end)
Enum.map(Stream.with_index(board), fn { line, y } ->
Enum.map(Stream.with_index(String.to_char_list(line)), fn
{ ?*, _ } -> ?* # Don't replace mines
{ _, x } -> case annotations[{x, y}] do
nil -> ?\s
n -> ?0 + n
end
end) |> to_string
end)
end
@adjacent_vecs for x <- [-1, 0, 1], y <- [-1, 0, 1], x != 0 or y != 0, do: { x, y }
defp add_adjacents(d, c, bounds) do
Enum.reduce(@adjacent_vecs, d, fn v, acc ->
c1 = add_vec(c, v)
if valid?(c1, bounds) do
Map.update(acc, c1, 1, &(&1+1))
else
acc
end
end)
end
defp add_vec({ cx, cy }, { vx, vy }), do: { cx + vx, cy + vy }
defp valid?({ cx, cy }, { w, h }), do: cx >= 0 and cx < w and cy >= 0 and cy < h
end
Version data entries
265 entries across 265 versions & 1 rubygems