I’ve decided to do this year’s advent of code in elixir as my first approach to the language. It’s been great but now on the second part of day 5 I’m facing a little problem. When I try to run the code on iex, the process gets killed after a little while. I’ve done a little investigating and appar…

Check out the size of the ranges. You are trying to allocate gargantuantic lists and you are asking where you get the memory usage from. Answer lies in the amount of data that you want to store.

defmodule Day5 do def read_file(path) do {:ok, contents} = File.read(path) String.split(contents, "\n\n", trim: true) end def create_almanac(sections) do almanac_object = %{ seed_numbers: nil, seed_ranges: [], to_soil: nil, to_fertilizer: nil, to_wate…

Yeah, I had taken the size of lists in consideration when writing the solution for the first part but totally forgot about that for this second part. I’ll write some code that doesn’t use lists. Thanks

You can usually get some benefit from changing Enum to Stream calls as the Stream functions are lazy and do not allocate all that memory up front with each call.

Using Streams apparently didn’t cut it. I’ll just not use lists. Thanks anyways

I had the same problem, took a while to figure out. Had to think in terms of ranges and not individual numbers.

[image] WallysFerreira: Enum.min(locations) General tip about AoC problems: a favorite “part 2” tactic is to expand the problem in a way that makes inefficient solutions intractable. For instance, the solution for my day 5 part 2 was ~15 million so locations would likely be LARGE There’s ano…

Yeah when the ranges are massive even lazy evaluation is going to eat up memory. Like others have said, thinking in terms other than evaluating each item is key for this sort of problem.

Can you show how you tried using Streams?

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Using too much memory

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WallysFerreira December 29, 2023, 2:58pm 7

Oooh that’s great. I’ll give it a try