53 lines
2.1 KiB
Text
53 lines
2.1 KiB
Text
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\--- Day 6: Signals and Noise ---
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----------
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Something is jamming your communications with Santa. Fortunately, your signal is only partially jammed, and protocol in situations like this is to switch to a simple [repetition code](https://en.wikipedia.org/wiki/Repetition_code) to get the message through.
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In this model, the same message is sent repeatedly. You've recorded the repeating message signal (your puzzle input), but the data seems quite corrupted - almost too badly to recover. *Almost*.
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All you need to do is figure out which character is most frequent for each position. For example, suppose you had recorded the following messages:
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```
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eedadn
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drvtee
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eandsr
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raavrd
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atevrs
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tsrnev
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sdttsa
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rasrtv
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nssdts
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ntnada
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svetve
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tesnvt
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vntsnd
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vrdear
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dvrsen
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enarar
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```
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The most common character in the first column is `e`; in the second, `a`; in the third, `s`, and so on. Combining these characters returns the error-corrected message, `easter`.
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Given the recording in your puzzle input, *what is the error-corrected version* of the message being sent?
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Your puzzle answer was `xdkzukcf`.
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\--- Part Two ---
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----------
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Of course, that *would* be the message - if you hadn't agreed to use a *modified repetition code* instead.
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In this modified code, the sender instead transmits what looks like random data, but for each character, the character they actually want to send is *slightly less likely* than the others. Even after signal-jamming noise, you can look at the letter distributions in each column and choose the *least common* letter to reconstruct the original message.
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In the above example, the least common character in the first column is `a`; in the second, `d`, and so on. Repeating this process for the remaining characters produces the original message, `advent`.
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Given the recording in your puzzle input and this new decoding methodology, *what is the original message* that Santa is trying to send?
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Your puzzle answer was `cevsgyvd`.
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Both parts of this puzzle are complete! They provide two gold stars: \*\*
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At this point, all that is left is for you to [admire your Advent calendar](/2016).
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If you still want to see it, you can [get your puzzle input](6/input).
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