Andrew Fontaine

Mostly code

More intcode computing! Without any modifications to the computer, and a quick search for an algorithm to make permutations, which, like, I just didn’t want to have to figure out, and I am ready to solve this.

  defp permutations([]), do: [[]]

  defp permutations(list),
    do: for(elem <- list, rest <- permutations(list -- [elem]), do: [elem | rest])

Once my permutations are generated, all that’s left is to amp things up.

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Today, I’m pretty much playing Kerbal Space Program and planning some orbital trajectories. As shown in the problem itself, a tree is the perfect way to represent the orbits, so building one shouldn’t be too hard.

  defp build_tree([], node), do: node

  defp build_tree(list, p) do
    connections = Enum.filter(list, &String.starts_with?(&1, p))

    list = Enum.filter(list, fn x -> x not in connections end)

    c =
      |> x -> x |> String.split(")") |> List.last() end)
      |> x -> build_tree(list, x) end)

    %{p: p, children: c}

list here is the list of connections I’m given, in the form of AAA)BBB, and p is the object that I am finding satellites of. First, I find all the connections by filtering the list for lines that start with the payload, and then for each child I build a tree with that child as the root. Once all the lines are filtered out, the tree is complete.

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In which previous bad code shoots me in the foot.

This was a continuation of the puzzle from day 2. If you don’t recall, I made a small intcode computer that was able to add, multiply, and stop. I need to augment this computer by adding the ability to take input and produce output. I also need to handle “parameter modes” and expanded intcodes

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This one didn’t seem too bad, but I can’t help but feel there’s a “clever” solution that alludes me. Some sort of funky math theorizing that I just don’t know about.

Puzzle 1

Put on your hacker gloves, it’s time to crack some passwords!

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After 3 puzzles, I am taking a look at how things are set up, and making a few tweaks.


My projections just do not work. It gets confused when trying to call :A on a test file, going to or making a source file instead of jumping to the appropriate puzzle file. To alleviate this, I needed to make some alterations:

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