88 lines
2.6 KiB
Markdown
88 lines
2.6 KiB
Markdown
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---
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permalink: "/{{ year }}/{{ month }}/{{ day }}/select-solution-from-aoc-where-year-2022"
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title: "SELECT solution FROM aoc WHERE year = 2022"
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published_date: "2022-12-09 11:20:00 +0100"
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layout: post.liquid
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data:
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route: blog
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---
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Every year [Advent of Code][aoc] happens.
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Every year I'm not super enthusiastic to actually solve those challenges.
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Every year I still start (and then maybe stop after some days).
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2022 was similar.
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I don't have a new programming language to learn and I still write enough code day-by-day that more coding is not really necessary.
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But yet sometimes it can be kind of nice to have a small challenge with a clear solution to go for
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and so I set myself some rules and went ahead.
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## My own rules
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* Solve it in SQL.
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* I started to run that in [BigQuery], but moved to [SQLite].
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* Only the SQL the system provides. How far can I take this?
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* It was easier on BigQuery with its large base of functionality, including string procesing, arrays, structs, ...
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* On SQLite initially I tried to avoid any custom functionality, I later relaxed this rule: [SQLean] is okay occasionally.
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* Once (so far) I used Python to preprocess the data. SQL is just really not good at text processing.
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* Getting the solution once is good enough.
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* The code can be ugly, messy and inefficient.
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* I don't write tests.
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* I do test. Just manually against the test input.
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* No persistent data.
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* It's all in-memory tables, CTEs, temporary views and a bunch of `SELECT`.
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* Learn some arcane SQL features.
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* Did you know SQL can recurse and select over windows? I do now!
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These are my rules. I break them when I feel like it.
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[AoC]: https://adventofcode.com/
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[bigquery]: https://cloud.google.com/bigquery/
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[sqlite]: https://sqlite.org/
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[sqlean]: https://github.com/nalgeon/sqlean
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## Sneak peek of day 1
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`SELECT solution FROM aoc WHERE year = 2022 AND day = 1;`
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I plan to release my solutions publicly, but I haven't yet.
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So for now you get my solution to day 1:
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```sql
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CREATE TABLE data(raw);
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.import input01.txt data
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WITH
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groups AS (
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SELECT rowid, ROW_NUMBER() OVER (ORDER BY rowid) cat FROM data WHERE raw = ''
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),
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elves AS (
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SELECT
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COALESCE(
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(SELECT cat FROM groups WHERE data.rowid < groups.rowid LIMIT 1),
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(SELECT cat + 1 FROM groups ORDER BY cat DESC LIMIT 1)
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) AS elf,
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raw as calories
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FROM data WHERE raw != ''
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),
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part1 AS (
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SELECT
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elf,
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SUM(calories) AS total_calories
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FROM elves
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GROUP BY 1
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ORDER BY 2 DESC
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)
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--SELECT * FROM part1;
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SELECT SUM(total_calories) as best_3 FROM (
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SELECT * FROM part1 LIMIT 3
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);
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```
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Runnable as:
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```
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sqlite3 < aoc01.sql
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```
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(Oh, another rule: It needs to run as `sqlite3 < script.sql`)
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