Day 9: Mirage Maintenance
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- Code block support is not fully rolled out yet but likely will be in the middle of the event. Try to share solutions as both code blocks and using something such as https://topaz.github.io/paste/ , pastebin, or github (code blocks to future proof it for when 0.19 comes out and since code blocks currently function in some apps and some instances as well if they are running a 0.19 beta)
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
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Python
Easy one today
code
import pathlib
base_dir = pathlib.Path(__file__).parent
filename = base_dir / "day9_input.txt"
with open(base_dir / filename) as f:
lines = f.read().splitlines()
histories = [[int(n) for n in line.split()] for line in lines]
answer_p1 = 0
answer_p2 = 0
for history in histories:
deltas: list[list[int]] = []
last_line: list[int] = history
while any(last_line):
deltas.append(last_line)
last_line = [last_line[i] - last_line[i - 1] for i in range(1, len(last_line))]
first_value = 0
last_value = 0
for delta_list in reversed(deltas):
last_value = delta_list[-1] + last_value
first_value = delta_list[0] - first_value
answer_p1 += last_value
answer_p2 += first_value
print(f"{answer_p1=}")
print(f"{answer_p2=}")