ABC044A - 高橋君とホテルイージー

問題

https://atcoder.jp/contests/abc044/tasks/abc044_a

回答

defmodule Main do
  def main do
    :stdio
    |> IO.read(:all)
    |> solve()
    |> IO.puts()
  end

  defp split_lines(lines) do
    lines
    |> String.trim()
    |> String.split("\n")
  end

  def solve(input) do
    [n, k, x, y] =
      input
      |> split_lines()
      |> Enum.map(&String.to_integer/1)

    cond do
      n <= k -> n * x
      true -> k * x + (n - k) * y
    end
  end
end

"""
5
3
10000
9000
"""
|> Main.solve()
|> then(&(&1 == 48000))

"""
2
3
10000
9000
"""
|> Main.solve()
|> then(&(&1 == 20000))