50 lines
2.0 KiB
Markdown
50 lines
2.0 KiB
Markdown
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# Day 8: Haunted Wasteland
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## Part 1
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You're still riding a camel across Desert Island when you spot a sandstorm quickly approaching. When you turn to warn
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the Elf, she disappears before your eyes! To be fair, she had just finished warning you about **ghosts** a few minutes
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ago.
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One of the camel's pouches is labeled "maps" - sure enough, it's full of documents (your puzzle input) about how to
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navigate the desert. At least, you're pretty sure that's what they are; one of the documents contains a list of
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left/right instructions, and the rest of the documents seem to describe some kind of **network** of labeled nodes.
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It seems like you're meant to use the **left/right** instructions to **navigate the network**. Perhaps if you have the
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camel follow the same instructions, you can escape the haunted wasteland!
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After examining the maps for a bit, two nodes stick out: `AAA` and `ZZZ`. You feel like `AAA` is where you are now,
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and you have to follow the left/right instructions until you reach `ZZZ`.
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This format defines each **node** of the network individually. For example:
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```
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RL
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AAA = (BBB, CCC)
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BBB = (DDD, EEE)
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CCC = (ZZZ, GGG)
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DDD = (DDD, DDD)
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EEE = (EEE, EEE)
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GGG = (GGG, GGG)
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ZZZ = (ZZZ, ZZZ)
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```
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Starting with `AAA`, you need to **look up the next element** based on the next left/right instruction in your input.
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In this example, start with `AAA` and go **right** (R) by choosing the right element of `AAA`, **CCC**. Then, `L` means
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to choose the **left** element of `CCC`, **ZZZ**. By following the left/right instructions, you reach `ZZZ` in 2 steps.
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Of course, you might not find `ZZZ` right away. If you run out of left/right instructions, repeat the whole sequence of
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instructions as necessary: `R`L really means `RLRLRLRLRLRLRLRL...` and so on. For example, here is a situation that
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takes `6` steps to reach `ZZZ`:
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```
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LLR
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AAA = (BBB, BBB)
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BBB = (AAA, ZZZ)
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ZZZ = (ZZZ, ZZZ)
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```
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Starting at AAA, follow the left/right instructions. **How many steps are required to reach ZZZ**?
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