brian/adventofcode
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Forgot to add the problem

Browse Source
This commit is contained in:
Brian Buller 2017-12-09 10:24:16 -06:00
parent 52faafccdf
commit f2e9ae4420
1 changed files with 99 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

99
2017/day09/problem Normal file
View File

@ -0,0 +1,99 @@
Advent of Code
--- Day 9: Stream Processing ---
A large stream blocks your path. According to the locals, it's not safe to cross the stream at the moment because it's full of garbage. You look down at the
stream; rather than water, you discover that it's a stream of characters.
You sit for a while and record part of the stream (your puzzle input). The characters represent groups - sequences that begin with { and end with }. Within a
group, there are zero or more other things, separated by commas: either another group or garbage. Since groups can contain other groups, a } only closes the
most-recently-opened unclosed group - that is, they are nestable. Your puzzle input represents a single, large group which itself contains many smaller ones.
Sometimes, instead of a group, you will find garbage. Garbage begins with < and ends with >. Between those angle brackets, almost any character can appear,
including { and }. Within garbage, < has no special meaning.
In a futile attempt to clean up the garbage, some program has canceled some of the characters within it using !: inside garbage, any character that comes after
! should be ignored, including <, >, and even another !.
You don't see any characters that deviate from these rules. Outside garbage, you only find well-formed groups, and garbage always terminates according to the
rules above.
Here are some self-contained pieces of garbage:
* <>, empty garbage.
* <random characters>, garbage containing random characters.
* <<<<>, because the extra < are ignored.
* <{!>}>, because the first > is canceled.
* <!!>, because the second ! is canceled, allowing the > to terminate the garbage.
* <!!!>>, because the second ! and the first > are canceled.
* <{o"i!a,<{i<a>, which ends at the first >.
Here are some examples of whole streams and the number of groups they contain:
* {}, 1 group.
* {{{}}}, 3 groups.
* {{},{}}, also 3 groups.
* {{{},{},{{}}}}, 6 groups.
* {<{},{},{{}}>}, 1 group (which itself contains garbage).
* {<a>,<a>,<a>,<a>}, 1 group.
* {{<a>},{<a>},{<a>},{<a>}}, 5 groups.
* {{<!>},{<!>},{<!>},{<a>}}, 2 groups (since all but the last > are canceled).
Your goal is to find the total score for all groups in your input. Each group is assigned a score which is one more than the score of the group that immediately
contains it. (The outermost group gets a score of 1.)
* {}, score of 1.
* {{{}}}, score of 1 + 2 + 3 = 6.
* {{},{}}, score of 1 + 2 + 2 = 5.
* {{{},{},{{}}}}, score of 1 + 2 + 3 + 3 + 3 + 4 = 16.
* {<a>,<a>,<a>,<a>}, score of 1.
* {{<ab>},{<ab>},{<ab>},{<ab>}}, score of 1 + 2 + 2 + 2 + 2 = 9.
* {{<!!>},{<!!>},{<!!>},{<!!>}}, score of 1 + 2 + 2 + 2 + 2 = 9.
* {{<a!>},{<a!>},{<a!>},{<ab>}}, score of 1 + 2 = 3.
What is the total score for all groups in your input?
Your puzzle answer was ______.
--- Part Two ---
Now, you're ready to remove the garbage.
To prove you've removed it, you need to count all of the characters within the garbage. The leading and trailing < and > don't count, nor do any canceled
characters or the ! doing the canceling.
* <>, 0 characters.
* <random characters>, 17 characters.
* <<<<>, 3 characters.
* <{!>}>, 2 characters.
* <!!>, 0 characters.
* <!!!>>, 0 characters.
* <{o"i!a,<{i<a>, 10 characters.
How many non-canceled characters are within the garbage in your puzzle input?
Your puzzle answer was ______.
Both parts of this puzzle are complete! They provide two gold stars: **
At this point, you should return to your advent calendar and try another puzzle.
If you still want to see it, you can get your puzzle input.
References
Visible links
. http://adventofcode.com/
. http://adventofcode.com/2017/about
. http://adventofcode.com/2017/support
. http://adventofcode.com/2017/events
. http://adventofcode.com/2017/settings
. http://adventofcode.com/2017/auth/logout
. http://adventofcode.com/2017
. http://adventofcode.com/2017
. http://adventofcode.com/2017/leaderboard
. http://adventofcode.com/2017/stats
. http://adventofcode.com/2017/sponsors
. http://adventofcode.com/2017/sponsors
. http://adventofcode.com/2017
. http://adventofcode.com/2017/day/9/input