Source: Boiling Boulders

Part 1

Given a list of 1x1x1 cubes, determine the total surface area of the cubes.

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Source: Pyroclastic Flow

Part 1

Simulate Tetris on a 7 wide board with a given (infinitely repeated) series of left and right inputs to be applied on each frame before dropping the block and a given (infinitely repeated) set of blocks. Once 2022 blocks have been dropped, what is the total height of the placed blocks?

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Source: Proboscidea Volcanium

Part 1

Given a graph of nodes, some of which have a pressure (per tick output value) and an agent that can move through the graph and activate specific nodes (so that they output their per tick value every future tick), what is the maximum total output possible in 30 steps?

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Source: Beacon Exclusion Zone

Part 1

There are a collections of Sensors and Beacons. As input, you are given the Beacon closest to each Sensor (using Manhattan Distance). If a Beacon is not closest to any sensor, it will not appear in this list. Calculate how many points in the given row (y=2000000) cannot contain a Beacon.

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Source: Regolith Reservoir

Part 1

Given a series of walls as input, run a falling sand simulation until any new sand falls of the map. Count how many grains of sand we end up with.

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Source: Distress Signal

Part 1

Given pairs of Signals (where a Signal is a nested list ;example: [[1],[2,3,4]]), count how many pairs are ‘in order’.

One Signal is less than the other if:

• Both are an integer and the first is less than the second
• Both are a list and the first value is less than the second
  • If the first values are the same, compare the second
  • If the first has fewer elements, it is treated as less than the second
• When comparing an integer and a list, wrap the integer as a single element list and compare them

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Source: Hill Climbing Algorithm

Part 1

Given a height map, find the shortest path between two points such that the path can descend any distance but can only climb by a maximum of 1.

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Source: Monkey in the Middle

Part 1

Simulate a collection of ‘monkeys’. Each monkey will have a number of items which it will then apply a mathematical operation to, then always divide by 3, then test divisibility to pass to one of two other monkeys. Return as answer the product of the two highest number of times a monkey applies it’s main function to individual items after 20 steps.

Note: Monkeys will always be evaluated in order (so monkey 1 will evaluate any items passed by monkey 0 again in the same round).

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Source: Cathode-Ray Tube

Part 1

Implement a simple virtual machine with two instructions: nop which does nothing for 1 cycles and addx $n which adds $n to the X register (initial value 1) in two cycles. Calculate the sum of cycle * X for the cycles 20, 60, 100, 140, 180, 220.

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Source: Rope Bridge

Part 1

Simulate two connected links such that whenever the first link (head) moves, the tail moves to follow according to the following rules:

• If the tail is at the same location as head, don’t move
• If the tail is adjacent to the head (orthogonal or diagonal), don’t move
• If the tail is in the same row/column as the head, move one directly towards it orthogonally
• If the tail is in neither the same row nor column, move one towards diagonally

Count how many unique spaces are visited by the tail of the link.

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