[1]Advent of Code
   br0xen [7](AoC++) 22*

--- Day 11: Reactor ---

   You hear some loud beeping coming from a hatch in the floor of the
   factory, so you decide to check it out. Inside, you find several large
   electrical conduits and a ladder.

   Climbing down the ladder, you discover the source of the beeping: a large,
   toroidal reactor which powers the factory above. Some Elves here are
   hurriedly running between the reactor and a nearby server rack, apparently
   trying to fix something.

   One of the Elves notices you and rushes over. "It's a good thing you're
   here! We just installed a new server rack, but we aren't having any luck
   getting the reactor to communicate with it!" You glance around the room
   and see a tangle of cables and devices running from the server rack to the
   reactor. She rushes off, returning a moment later with a list of the
   devices and their outputs (your puzzle input).

   For example:

 aaa: you hhh
 you: bbb ccc
 bbb: ddd eee
 ccc: ddd eee fff
 ddd: ggg
 eee: out
 fff: out
 ggg: out
 hhh: ccc fff iii
 iii: out

   Each line gives the name of a device followed by a list of the devices to
   which its outputs are attached. So, bbb: ddd eee means that device bbb has
   two outputs, one leading to device ddd and the other leading to device
   eee.

   The Elves are pretty sure that the issue isn't due to any specific device,
   but rather that the issue is triggered by data following some specific
   path through the devices. Data only ever flows from a device through its
   outputs; it can't flow backwards.

   After dividing up the work, the Elves would like you to focus on the
   devices starting with the one next to you (an Elf hastily attaches a label
   which just says you) and ending with the main output to the reactor (which
   is the device with the label out).

   To help the Elves figure out which path is causing the issue, they need
   you to find every path from you to out.

   In this example, these are all of the paths from you to out:

     • Data could take the connection from you to bbb, then from bbb to ddd,
       then from ddd to ggg, then from ggg to out.
     • Data could take the connection to bbb, then to eee, then to out.
     • Data could go to ccc, then ddd, then ggg, then out.
     • Data could go to ccc, then eee, then out.
     • Data could go to ccc, then fff, then out.

   In total, there are 5 different paths leading from you to out.

   How many different paths lead from you to out?

   Your puzzle answer was 585.

--- Part Two ---

   Thanks in part to your analysis, the Elves have figured out a little bit
   about the issue. They now know that the problematic data path passes
   through both dac (a [16]digital-to-analog converter) and fft (a device
   which performs a [17]fast Fourier transform).

   They're still not sure which specific path is the problem, and so they now
   need you to find every path from svr (the server rack) to out. However,
   the paths you find must all also visit both dac and fft (in any order).

   For example:

 svr: aaa bbb
 aaa: fft
 fft: ccc
 bbb: tty
 tty: ccc
 ccc: ddd eee
 ddd: hub
 hub: fff
 eee: dac
 dac: fff
 fff: ggg hhh
 ggg: out
 hhh: out

   This new list of devices contains many paths from svr to out:

 svr,aaa,fft,ccc,ddd,hub,fff,ggg,out
 svr,aaa,fft,ccc,ddd,hub,fff,hhh,out
 svr,aaa,fft,ccc,eee,dac,fff,ggg,out
 svr,aaa,fft,ccc,eee,dac,fff,hhh,out
 svr,bbb,tty,ccc,ddd,hub,fff,ggg,out
 svr,bbb,tty,ccc,ddd,hub,fff,hhh,out
 svr,bbb,tty,ccc,eee,dac,fff,ggg,out
 svr,bbb,tty,ccc,eee,dac,fff,hhh,out

   However, only 2 paths from svr to out visit both dac and fft.

   Find all of the paths that lead from svr to out. How many of those paths
   visit both dac and fft?

   Your puzzle answer was 349322478796032.

   Both parts of this puzzle are complete! They provide two gold stars: **

   At this point, you should [18]return to your Advent calendar and try
   another puzzle.

   If you still want to see it, you can [19]get your puzzle input.

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