Pt 1 was easy, Pt 2 was pure horror.
Earlier drafts of the code tried to be way too
smart. At one point, I just came to the conclusion
to place a new obstacle (#) on the grid and just
rerun the thing to look for loops.
2 things:
- the visited positions from pt 1 can be used as a
subset for positions to consider for the extra
"#".
- The track of loops can be optimized to look at
bounces on "#"s instead of each individual y,x pos,
given that the direction is remembered.
pt 2 is familiar, the last time a puzzle required
look detection the puzzle used lazer beams and
reflectors. Not sure what Event or day it was.
In p2, it took some tries to find a correct way
to rearrange incorrect pagesets. The code ended
up just rearranging first found incorrect order
and readding the updated pageset to queue.
Felt paranoid on this one, was expecting something
much worse for pt2.
The code that solved the puzzle was _extremely_
naive:
- It asumes puzzle input only contains mul() with
1-3 chars. The versioned code have `{1,3}` as safe
guard.
- p2 asumed initial chunk does not begin with
"n't". Would have been easy to handle though.
- p2 asumed junk strings as "don", "do", "don()t"
would not exist.
In other words, I was really lucky since I did not
look that closely on puzzle input beforehand.
Might have cut 60-90 seconds further if I had just
ran pt2 immidately instead of staring dumbly on the
test data (that changed for pt2).
Also, I got reminded that \d in regular expressions
is equal to `0-9`: it does not include commas and
punctations. The code that solved the puzzle was
paranoid and instead used `0-9`.
Managed to score ~1500th somehow despite this.
DDOS of adventofcode.com, did not get to open the
puzzle until 06:05 (five minutes local time).
Screwed up the zip() and lost valuable minutes by
trying to replace it with itertools, only to find
I have made a typo (did AB CD EF instead of AB BC
CD).
I also lost valuable minutes by tring to solve p1
with one nested loop. Stupid.
For part 2, I created the issafe() helper to be
able to remove items from reports and test, one
at the time.
Realized afterwards I got the ints() helper, so
original code before cleanup splitted the input and
mapped all words with int(). valuable seconds lost
there.
Also, collections.Counter() was used initially since
I was too tired to remember count() method in lists.
Line 8 took the longest time to figure out. A typo
took 1-3 minutes to find for part 2.
Form: Sleep deprived, felt slow.
