---
title: "Discussion on \"Advent of Code 2020: Day 9 (Ruby solution)\" | Hashnode"
description: "Discussion on \"Advent of Code 2020: Day 9 (Ruby solution)\". Today's puzzles  are about debugging a stream of some fake protocol.\nThe first task is to find the first value that violates protocol rules. It means finding the first number in the list (after the preamble) which is not the sum of two of the 25 numb..."
url: "https://hashnode.com/posts/advent-of-code-2020-day-9-ruby-solution/5fd0b982e44fe338abffbfb1"
---

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# [Advent of Code 2020: Day 9 (Ruby solution)](https://rubywizards.com/advent-of-code-2020-day-9-ruby-solution?utm_source=hashnode&utm_medium=feed)

Today's puzzles are about debugging a stream of some fake protocol. The first task is to find the first value that violates protocol rules. It means finding the first number in the list (after the preamble) which is not the sum of two of the 25 numb...

Dec 9, 2020 · 1 min read · rubywizards.com  
Updated Apr 13, 2021  
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-   [#ruby](https://hashnode.com/tag/ruby)

## Written by

[Piotr Jurewicz](https://hashnode.com/@pjurewicz)

@pjurewicz · Łódź, Poland

  
[View profile](https://hashnode.com/@pjurewicz)

ruby on rails developer

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