[2023] [Day 21]: Step Counter #221
Comments
Challenge link |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
{{ message }}
Challenge link |
Challenge description
You manage to catch the airship right as it's dropping someone else off on their all-expenses-paid trip to Desert Island! It even helpfully drops you off near the gardener and his massive farm.
"You got the sand flowing again! Great work! Now we just need to wait until we have enough sand to filter the water for Snow Island and we'll have snow again in no time."
While you wait, one of the Elves that works with the gardener heard how good you are at solving problems and would like your help. He needs to get his steps in for the day, and so he'd like to know which garden plots he can reach with exactly his remaining
64steps.He gives you an up-to-date map (your puzzle input) of his starting position (
S), garden plots (.), and rocks (#). For example:The Elf starts at the starting position (
S) which also counts as a garden plot. Then, he can take one step north, south, east, or west, but only onto tiles that are garden plots. This would allow him to reach any of the tiles markedO:Then, he takes a second step. Since at this point he could be at either tile marked
O, his second step would allow him to reach any garden plot that is one step north, south, east, or west of any tile that he could have reached after the first step:After two steps, he could be at any of the tiles marked
Oabove, including the starting position (either by going north-then-south or by going west-then-east).A single third step leads to even more possibilities:
He will continue like this until his steps for the day have been exhausted. After a total of
6steps, he could reach any of the garden plots markedO:In this example, if the Elf's goal was to get exactly
6more steps today, he could use them to reach any of16garden plots.However, the Elf actually needs to get
64steps today, and the map he's handed you is much larger than the example map.Starting from the garden plot marked
Son your map, how many garden plots could the Elf reach in exactly64steps?Challenge input
Challenge year
2023
The text was updated successfully, but these errors were encountered: