40 lines
1.3 KiB
Plaintext
40 lines
1.3 KiB
Plaintext
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--- Day 4: Ceres Search ---
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"Looks like the Chief's not here. Next!" One of The Historians pulls out a device and pushes the only button on it. After a brief flash, you recognize the interior of the Ceres monitoring station!
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As the search for the Chief continues, a small Elf who lives on the station tugs on your shirt; she'd like to know if you could help her with her word search (your puzzle input). She only has to find one word: XMAS.
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This word search allows words to be horizontal, vertical, diagonal, written backwards, or even overlapping other words. It's a little unusual, though, as you don't merely need to find one instance of XMAS - you need to find all of them. Here are a few ways XMAS might appear, where irrelevant characters have been replaced with .:
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..X...
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.SAMX.
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.A..A.
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XMAS.S
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.X....
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The actual word search will be full of letters instead. For example:
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MMMSXXMASM
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MSAMXMSMSA
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AMXSXMAAMM
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MSAMASMSMX
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XMASAMXAMM
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XXAMMXXAMA
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SMSMSASXSS
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SAXAMASAAA
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MAMMMXMMMM
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MXMXAXMASX
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In this word search, XMAS occurs a total of 18 times; here's the same word search again, but where letters not involved in any XMAS have been replaced with .:
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....XXMAS.
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.SAMXMS...
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...S..A...
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..A.A.MS.X
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XMASAMX.MM
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X.....XA.A
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S.S.S.S.SS
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.A.A.A.A.A
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..M.M.M.MM
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.X.X.XMASX
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Take a look at the little Elf's word search. How many times does XMAS appear?
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To begin, get your puzzle input.
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