advent_of_code_2021

day06_part2.py (1511B)

---

 #!/usr/bin/env python
 """Advent of Code 2021, day 6 (part 2): simulate an exponentially growing
 school of lanternfish using an initial list of fish and their ages... for a
 longer period than part 1"""
 
 # I find myself metagaming a little bit: anticipating how part 2 will build
 # upon part 1, while trying to make it easy to accommodate in my existing code
 # without over-engineering things for functionality that won't become
 # necessary. IME, this is what being a programmer (including 'data scientist')
 # in the real world is actually like.
 #
 # In this case, I was imagining something more complicated, like: maybe there
 # are a couple different types of fish, or maybe the fish die eventually, or
 # maybe the spawn rate depends on the size of the school. But instead we're
 # doing something dead simple: running the same solution as before, but for
 # longer. I suspect that this is supposed to punish people who
 # implemented a list of fish instead of a set of counts.
 
 from day06_part1 import (convert_input_to_series,
                          count_fish_after)
 from utils import get_puzzle_input
 
 def solve_puzzle(input_string):
     """Return the numeric solution to the puzzle"""
     return count_fish_after(convert_input_to_series(input_string), 256)
 
 def main():
     """Run when the file is called as a script"""
     assert solve_puzzle("3,4,3,1,2\n") == 26984457539
     print("Number of lanternfish after 256 days:",
           solve_puzzle(get_puzzle_input(6)))
 
 if __name__ == "__main__":
     main()