part1

Advent of Code 2021 - Day 8 Part 1

In the output values, how many times do digits 1, 4, 7, or 8 appear?

Setup

Parse into a list of 2-elem tuples: first being a list of 10 unique patterns per display, second the list of 4 digit outputs.

Implementation

We drop the first list on the floor and only inspect the second for string lengths that match the unique segments we're looking for.

Running

mix run

Testing

mix test