Source: Day 11: Plutonian Pebbles

Full solution for today (spoilers!).

Part 1

Given a sequence of values v_n, replace each value with the first matching rule:

• if v = 0 -> 1
• If v has an even number of digits, split it (so v = 8675 becomes [86, 75])
• Otherwise, v -> v * 2024

Calculate how many elements are in the sequence after 25 iterations.

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