Solution to problem 9 in Python
This commit is contained in:
parent
8cdfec343b
commit
21622cc051
|
@ -0,0 +1,133 @@
|
|||
# --- 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?
|
||||
|
||||
with open("files/P9.txt") as f:
|
||||
data = [line for line in f.read().strip().split()][0]
|
||||
|
||||
|
||||
def part_1() -> None:
|
||||
group_count, score = 0, 0
|
||||
i = 0
|
||||
while i < len(data):
|
||||
if data[i] == "{":
|
||||
group_count += 1
|
||||
score += group_count
|
||||
elif data[i] == "}":
|
||||
group_count -= 1
|
||||
elif data[i] == "<":
|
||||
i += 1
|
||||
while data[i] != ">" and i < len(data):
|
||||
if data[i] == "!":
|
||||
i += 1
|
||||
i += 1
|
||||
i += 1
|
||||
|
||||
print(f"The total score is {score}")
|
||||
|
||||
|
||||
# --- 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?
|
||||
|
||||
|
||||
def part_2() -> None:
|
||||
group_count, score, garbage_chars = 0, 0, 0
|
||||
i = 0
|
||||
while i < len(data):
|
||||
if data[i] == "{":
|
||||
group_count += 1
|
||||
score += group_count
|
||||
elif data[i] == "}":
|
||||
group_count -= 1
|
||||
elif data[i] == "<":
|
||||
i += 1
|
||||
while data[i] != ">" and i < len(data):
|
||||
if data[i] == "!":
|
||||
i += 1
|
||||
else:
|
||||
garbage_chars += 1
|
||||
i += 1
|
||||
i += 1
|
||||
|
||||
print(f"There are {garbage_chars} non-cancelled characters in the garbage")
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
part_1()
|
||||
part_2()
|
Loading…
Reference in New Issue