96 lines
3.9 KiB
Plaintext
96 lines
3.9 KiB
Plaintext
Advent of Code
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--- Day 8: Matchsticks ---
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Space on the sleigh is limited this year, and so Santa will be bringing his
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list as a digital copy. He needs to know how much space it will take up when
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stored.
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It is common in many programming languages to provide a way to escape
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special characters in strings. For example, C, JavaScript, Perl, Python, and
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even PHP handle special characters in very similar ways.
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However, it is important to realize the difference between the number of
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characters in the code representation of the string literal and the number
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of characters in the in-memory string itself.
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For example:
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• "" is 2 characters of code (the two double quotes), but the string
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contains zero characters.
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• "abc" is 5 characters of code, but 3 characters in the string data.
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• "aaa\"aaa" is 10 characters of code, but the string itself contains six
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"a" characters and a single, escaped quote character, for a total of 7
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characters in the string data.
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• "\x27" is 6 characters of code, but the string itself contains just one
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- an apostrophe ('), escaped using hexadecimal notation.
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Santa's list is a file that contains many double-quoted string literals, one
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on each line. The only escape sequences used are \\ (which represents a
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single backslash), \" (which represents a lone double-quote character), and
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\x plus two hexadecimal characters (which represents a single character with
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that ASCII code).
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Disregarding the whitespace in the file, what is the number of characters of
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code for string literals minus the number of characters in memory for the
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values of the strings in total for the entire file?
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For example, given the four strings above, the total number of characters of
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string code (2 + 5 + 10 + 6 = 23) minus the total number of characters in
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memory for string values (0 + 3 + 7 + 1 = 11) is 23 - 11 = 12.
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Your puzzle answer was 1350.
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--- Part Two ---
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Now, let's go the other way. In addition to finding the number of characters
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of code, you should now encode each code representation as a new string and
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find the number of characters of the new encoded representation, including
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the surrounding double quotes.
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For example:
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• "" encodes to "\"\"", an increase from 2 characters to 6.
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• "abc" encodes to "\"abc\"", an increase from 5 characters to 9.
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• "aaa\"aaa" encodes to "\"aaa\\\"aaa\"", an increase from 10 characters
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to 16.
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• "\x27" encodes to "\"\\x27\"", an increase from 6 characters to 11.
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Your task is to find the total number of characters to represent the newly
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encoded strings minus the number of characters of code in each original
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string literal. For example, for the strings above, the total encoded length
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(6 + 9 + 16 + 11 = 42) minus the characters in the original code
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representation (23, just like in the first part of this puzzle) is 42 - 23 =
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19.
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Your puzzle answer was 2085.
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Both parts of this puzzle are complete! They provide two gold stars: **
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At this point, you should return to your advent calendar and try another puzzle.
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If you still want to see it, you can get your puzzle input.
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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/about
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. http://adventofcode.com/stats
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. http://adventofcode.com/leaderboard
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. http://adventofcode.com/settings
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. http://adventofcode.com/auth/logout
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. https://en.wikipedia.org/wiki/Escape_sequences_in_C
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. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String
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. http://perldoc.perl.org/perlop.html#Quote-and-Quote-like-Operators
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. https://docs.python.org/2.0/ref/strings.html
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. http://php.net/manual/en/language.types.string.php#language.types.string.syntax.double
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. http://adventofcode.com/
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. http://adventofcode.com/day/8/input
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