46 lines
1.7 KiB
Markdown
46 lines
1.7 KiB
Markdown
## \-\-- Day 19: A Series of Tubes \-\--
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Somehow, a network packet got
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lost
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and ended up here. It\'s trying to follow a routing diagram (your puzzle
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input), but it\'s confused about where to go.
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Its starting point is just off the top of the diagram. Lines (drawn with
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`|`, `-`, and `+`) show the path it needs to take, starting by going
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down onto the only line connected to the top of the diagram. It needs to
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follow this path until it reaches the end (located somewhere within the
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diagram) and stop there.
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Sometimes, the lines cross over each other; in these cases, it needs to
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continue going the same direction, and only turn left or right when
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there\'s no other option. In addition, someone has left *letters* on the
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line; these also don\'t change its direction, but it can use them to
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keep track of where it\'s been. For example:
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A | C
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F---|----E|--+
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| | | D
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+B-+ +--+
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Given this diagram, the packet needs to take the following path:
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- Starting at the only line touching the top of the diagram, it must
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go down, pass through `A`, and continue onward to the first `+`.
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- Travel right, up, and right, passing through `B` in the process.
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- Continue down (collecting `C`), right, and up (collecting `D`).
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- Finally, go all the way left through `E` and stopping at `F`.
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Following the path to the end, the letters it sees on its path are
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`ABCDEF`.
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The little packet looks up at you, hoping you can help it find the way.
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*What letters will it see* (in the order it would see them) if it
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follows the path? (The routing diagram is very wide; make sure you view
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it without line wrapping.)
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To begin, [get your puzzle input](19/input).
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Answer:
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