AoC 2024 Day 14: Chaosinator

Source: Day 14: Restroom Redoubt

Full solution for today (spoilers!).

Part 1

Given a series of robots defined with initial position and velocity on a 101x103 toroidal grid, calculate where the robots will be after 100 iterations. Return the product of the number of robots in each quadrant of the final grid, ignoring the middle lines (since they’re odd).

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AoC 2024 Day 11: Exponential Growthinator

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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AoC 2024 Day 9: Defraginator

Source: Day 9: Disk Fragmenter

Full solution for today (spoilers!).

Part 1

Given a disk layout alternating between files and empty spaces, move all files as early on the disk is possible, splitting into multiple blocks. Return a checksum on the disk.

Alternating means: 23331 would mean a 2 block file, 3 empty, a 3 block file, 3 empty, and a 1 block file.

The checksum is the sum of file_id * block_index for all occupied blocks. File IDs are assigned sequentially on initial generation.

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AoC 2024 Day 6: Wanderinator

Source: Day 6: Guard Gallivant

Full solution for today (spoilers!).

Part 1

You are given a grid of walls (#), floors (.), and a guard (^, initially facing up/north). The guard walks forward until they run into a wall at which point they turn right. How many tiles does the guard reach before leaving the map.

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