31 lines
1,023 B
Elixir
31 lines
1,023 B
Elixir
defmodule Day18Part1 do
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def run do
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File.stream!("input")
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|> Stream.map(&parse_line/1)
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|> Stream.map(&evaluate/1)
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|> Enum.sum()
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|> IO.puts()
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end
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def parse_line(line) do
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line
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|> String.graphemes()
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|> Stream.reject(fn char -> char in [" ", "\n"] end)
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|> Enum.map(fn
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symbol when symbol in ["*", "+", "(", ")"] -> symbol
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num -> String.to_integer(num)
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end)
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end
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def evaluate(command), do: evaluate(command, nil, 0)
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def evaluate([], nil, acc), do: acc
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def evaluate(["*" | rest], nil, acc), do: evaluate(rest, "*", acc)
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def evaluate(["+" | rest], nil, acc), do: evaluate(rest, "+", acc)
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def evaluate(["(" | rest], op, acc), do: evaluate(rest) |> evaluate(op, acc)
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def evaluate([")" | rest], nil, acc), do: [acc | rest]
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def evaluate([num | rest], "*", acc), do: evaluate(rest, nil, acc * num)
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def evaluate([num | rest], "+", acc), do: evaluate(rest, nil, acc + num)
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def evaluate([num | rest], nil, 0), do: evaluate(rest, nil, num)
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end
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Day18Part1.run()
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