Add 2015 Day4

This commit is contained in:
Adam Millerchip 2023-09-02 03:08:50 +09:00
parent f1762d886a
commit 550b652b45

50
2015/day4.exs Normal file
View file

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defmodule Day4 do
def part1(input), do: mine(input, 1, "00000")
def mine(input, nonce, prefix) do
hash = :crypto.hash(:md5, input <> Integer.to_string(nonce)) |> Base.encode16()
if String.starts_with?(hash, prefix), do: nonce, else: mine(input, nonce + 1, prefix)
end
def part2(input), do: mine(input, 1, "000000")
def input do
with [input] <- System.argv() do
input
else
_ -> :error
end
end
#######################
# HERE BE BOILERPLATE #
#######################
def run do
case input() do
:error -> print_usage()
input -> run_parts_with_timer(input)
end
end
defp run_parts_with_timer(input) do
run_with_timer(1, fn -> part1(input) end)
run_with_timer(2, fn -> part2(input) end)
end
defp run_with_timer(part, fun) do
{time, result} = :timer.tc(fun)
IO.puts("Part #{part} (completed in #{format_time(time)}):\n")
IO.puts("#{result}\n")
end
defp format_time(μsec) when μsec < 1_000, do: "#{μsec}μs"
defp format_time(μsec) when μsec < 1_000_000, do: "#{μsec / 1000}ms"
defp format_time(μsec), do: "#{μsec / 1_000_000}s"
defp print_usage do
IO.puts("Usage: elixir day4.exs input")
end
end
Day4.run()