78 lines
2.7 KiB
Plaintext
78 lines
2.7 KiB
Plaintext
Advent of Code
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--- Day 24: Air Duct Spelunking ---
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You've finally met your match; the doors that provide access to the roof are
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locked tight, and all of the controls and related electronics are
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inaccessible. You simply can't reach them.
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The robot that cleans the air ducts, however, can.
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It's not a very fast little robot, but you reconfigure it to be able to
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interface with some of the exposed wires that have been routed through the
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HVAC system. If you can direct it to each of those locations, you should be
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able to bypass the security controls.
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You extract the duct layout for this area from some blueprints you acquired
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and create a map with the relevant locations marked (your puzzle input). 0
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is your current location, from which the cleaning robot embarks; the other
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numbers are (in no particular order) the locations the robot needs to visit
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at least once each. Walls are marked as #, and open passages are marked as
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.. Numbers behave like open passages.
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For example, suppose you have a map like the following:
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###########
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#0.1.....2#
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#.#######.#
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#4.......3#
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###########
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To reach all of the points of interest as quickly as possible, you would
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have the robot take the following path:
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• 0 to 4 (2 steps)
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• 4 to 1 (4 steps; it can't move diagonally)
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• 1 to 2 (6 steps)
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• 2 to 3 (2 steps)
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Since the robot isn't very fast, you need to find it the shortest route.
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This path is the fewest steps (in the above example, a total of 14) required
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to start at 0 and then visit every other location at least once.
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Given your actual map, and starting from location 0, what is the fewest
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number of steps required to visit every non-0 number marked on the map at
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least once?
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Your puzzle answer was 490.
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--- Part Two ---
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Of course, if you leave the cleaning robot somewhere weird, someone is bound
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to notice.
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What is the fewest number of steps required to start at 0, visit every non-0
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number marked on the map at least once, and then return to 0?
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Your puzzle answer was 744.
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References
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Visible links
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. http://adventofcode.com/
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. http://adventofcode.com/2016/about
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. http://adventofcode.com/2016
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. http://adventofcode.com/2016/sponsors
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. http://adventofcode.com/2016/sponsors
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. https://en.wikipedia.org/wiki/HVAC
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. http://adventofcode.com/2016
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. http://adventofcode.com/2016/day/24/input
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