# --- Day 10: Elves Look, Elves Say ---

# Today, the Elves are playing a game called look-and-say. They take turns
# making sequences by reading aloud the previous sequence and using that
# reading as the next sequence. For example, 211 is read as "one two, two
# ones", which becomes 1221 (1 2, 2 1s).

# Look-and-say sequences are generated iteratively, using the previous value as
# input for the next step. For each step, take the previous value, and replace
# each run of digits (like 111) with the number of digits (3) followed by the
# digit itself (1).

# For example:

#     1 becomes 11 (1 copy of digit 1).
#     11 becomes 21 (2 copies of digit 1).
#     21 becomes 1211 (one 2 followed by one 1).
#     1211 becomes 111221 (one 1, one 2, and two 1s).
#     111221 becomes 312211 (three 1s, two 2s, and one 1).

# Starting with the digits in your puzzle input, apply this process 40 times.
# What is the length of the result?

from itertools import groupby


def part_1() -> None:
    num = "3113322113"
    for _ in range(40):
        num = "".join(str(len(list(g))) + k for k, g in groupby(num))

    print(f"After 40 iterations, the length is {len(num)}")


# --- Part Two ---

# Neat, right? You might also enjoy hearing John Conway talking about this
# sequence (that's Conway of Conway's Game of Life fame).

# Now, starting again with the digits in your puzzle input, apply this process
# 50 times. What is the length of the new result?


def part_2() -> None:
    num = "3113322113"
    for _ in range(50):
        num = "".join(str(len(list(g))) + k for k, g in groupby(num))

    print(f"After 50 iterations, the length is {len(num)}")


if __name__ == "__main__":
    part_1()
    part_2()