45 lines
2.6 KiB
Markdown
45 lines
2.6 KiB
Markdown
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# Day 2: Cube Conundrum
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## Part 1
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You're launched high into the atmosphere! The apex of your trajectory just barely reaches the surface of a large island
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floating in the sky. You gently land in a fluffy pile of leaves. It's quite cold, but you don't see much snow. An Elf
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runs over to greet you.
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The Elf explains that you've arrived at Snow Island and apologizes for the lack of snow. He'll be happy to explain the
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situation, but it's a bit of a walk, so you have some time. They don't get many visitors up here; would you like to
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play a game in the meantime?
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As you walk, the Elf shows you a small bag and some cubes which are either red, green, or blue. Each time you play
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this game, he will hide a secret number of cubes of each color in the bag, and your goal is to figure out information
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about the number of cubes.
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To get information, once a bag has been loaded with cubes, the Elf will reach into the bag, grab a handful of random
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cubes, show them to you, and then put them back in the bag. He'll do this a few times per game.
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You play several games and record the information from each game (your puzzle input). Each game is listed with its ID
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number (like the 11 in Game 11: ...) followed by a semicolon-separated list of subsets of cubes that were revealed
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from the bag (like 3 red, 5 green, 4 blue).
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For example, the record of a few games might look like this:
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Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
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Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
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Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
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Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
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Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green
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In game 1, three sets of cubes are revealed from the bag (and then put back again). The first set is 3 blue cubes and
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4 red cubes; the second set is 1 red cube, 2 green cubes, and 6 blue cubes; the third set is only 2 green cubes.
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The Elf would first like to know which games would have been possible if the bag contained only 12 red cubes,
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13 green cubes, and 14 blue cubes?
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In the example above, games 1, 2, and 5 would have been possible if the bag had been loaded with that configuration.
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However, game 3 would have been impossible because at one point the Elf showed you 20 red cubes at once;
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similarly, game 4 would also have been impossible because the Elf showed you 15 blue cubes at once. If you add up the
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IDs of the games that would have been possible, you get 8.
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Determine which games would have been possible if the bag had been loaded with only 12 red cubes, 13 green cubes, and
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14 blue cubes. What is the sum of the IDs of those games?
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