I wish Advent of Code puzzles were strictly algorithm focused without relying on specifics of mathematics. Skipping puzzles is demotivating for the completionist in me that lacks time to re-read math books.
Perhaps a compromise would be to start with an easy input that any pile of if statements can handle, then give a longer input that will break all but the best algorithms as a bonus.
Granted, I don't know the process of AoC in terms of vetting and building their puzzles, but it seems that the person/people involved all share very similar levels and domain of knowledge. Having more people reviewing or involved in the process that have a wider range of skillsets might avoid these situations.
Example from what I was talking about before: Day 13 of AoC2020 was basically "the answer is the Chinese Remainder Theorem". If you remembered that...great you could solve this in 10 seconds (hell some languages have a _function_ for that theorem!). If not....well good luck finding a solution that runs in under 6h. That has nothing to do with _programming_. Its just math, there wasn't even programming involved (literally some solutions were just "parse the input and pass it to mathlib.chinese_remainder()"). That's not satisfying to solve for the majority of people, I feel (opinion, I know).
result = 0
addend = 1
for divisor, desired_offset in [(7, 0), (13, 1), (59, 4), (31, 6), (19, 7)]:
# keep trying numbers until we find the one that, with
# the desired offset added to it, would divide without
# remainder
while (result + desired_offset) % divisor != 0:
result += addend
# adding another addend should not break previous results
# so make it divisible by all previous divisors
addend *= divisor
result %= 7*13*59*31*19 # Is it really needed? Eh.
print(result)