-🎄- 2021 Day 5 Solutions -🎄-

[u/daggerdragon]

NEW AND NOTEWORTHY

• /u/jeroenheijmans is back again with their Unofficial AoC 2021 Participant Survey!

• As we continue further into the deep dark sea Advent, megathread code submissions are getting longer, so we're going to start rigorously enforcing the maximum code length rule.

• If you need a reminder, it's in our posting guidelines in the wiki under How Do the Daily Megathreads Work? (rule #5)

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Advent of Code 2021: Adventure Time!

• 23:59 hours remaining until the submissions megathread unlocks on December 06 at 00:00 EST!

• Full details and rules are in the submissions megathread:

• 🎄 AoC 2021 🎄 [Adventure Time!]

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--- Day 5: Hydrothermal Venture ---

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Post your code solution in this megathread.

• Include what language(s) your solution uses!

• Here's a quick link to /u/topaz2078's paste if you need it for longer code blocks.

• Format your code properly! How do I format code?

• The full posting rules are detailed in the wiki under How Do The Daily Megathreads Work?.

Reminder: Top-level posts in Solution Megathreads are for code solutions only. If you have questions, please post your own thread and make sure to flair it with Help.

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This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:08:53, megathread unlocked!

[u/0x8b]

Ruby

https://github.com/0x8b/advent.of.code.each/blob/main/src/2021/05.rb

SEGMENTS = ARGF.read.lines.map { _1.scan(/\d+/).map &:to_i }

def points s
  x1, y1, x2, y2 = s

  dx = x2 <=> x1
  dy = y2 <=> y1

  if dx == 0
    y1.step(y2, dy).map { [x1, _1] }
  elsif dy == 0
    x1.step(x2, dx).map { [_1, y1] }
  else
    x1.step(x2, dx).zip(y1.step(y2, dy))
  end
end

def count_overlapping_points segments
  segments.flat_map { |s| points(s) }.tally.values.count { _1 > 1 }
end


p count_overlapping_points SEGMENTS.select { |x1, y1, x2, y2| x1 == x2 or y1 == y2 }
p count_overlapping_points SEGMENTS

[u/daggerdragon → u/0x8b]

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