AoC 2021 Day 22: Cubinator

2021-12-22

Source: Reactor Reboot

Part 1: Given a series of 3D cubes that either turn ON all or turn OFF all points in their region, calculate how many points in the region (-50..50,-50..50,-50..50) are ON at the end.

AoC 2021 Day 21: Dicinator

2021-12-21

Source: Dirac Dice

Part 1: Play a simple game (describe below) with a loaded D100 (that always rolls 1, 2, 3, … 99, 100, 1, …). Return the score of the losing player times the number of times the die was rolled.

AoC 2021 Day 20: Enhancinator

2021-12-20

Source: Trench Map

Part 1: Given a 9->1 cellular automota update function (take the pixel and 8 surrounding pixels as a 9-bit index into the function) and a binary image, apply the function twice and count the number of ’lit’ pixels. Assume that the canvas is infinite.

AoC 2021 Day 19: Point Matchinator

2021-12-19

Source: Snailfish

Part 1: You will be given a series of Scanners, each of which will tell you the location (from their point of view) of a series of Beacons. Each Scanner may be flipped or rotated in increments of 90 degrees in any direction. Determine where each Scanner and Beacon is by overlaying the maps (with at least pairwise 12 matches).

AoC 2021 Day 18: Pairs of Pairs

2021-12-18

Source: Snailfish

Part 1: Given the following definition of Snailfish numbers, add a series of Snailfish numbers and return the magnitude of the result.

AoC 2021 Day 17: Pew-Pewinator

2021-12-17

Source: Trick Shot

Part 1: Simulate a projectile with an integer initial velocity (x, y), air resistance that tries to reduce x-velocity to 0, and gravity that increases y-velocity by 1 each time. Given a target range, find the highest point reached by a projectile that ends a tick (not one that crosses over) within the target area.

AoC 2021 Day 16: Depacketinator

2021-12-16

Source: Packet Decoder

Part 1: Given a recursive binary packet definition (see below), parse the given packet. Return the sum of each packet’s `version`.

AoC 2021 Day 15: Low Ceiling Simulator

2021-12-15

Source: Chiton

Part 1: Given a grid of weights, find the minimum path from top left to top right. Return the total weight along that path.

AoC 2021 Day 14: Polymerizationinator

2021-12-14

Source: Extended Polymerization

Part 1: Given a complete function `f(a, b) -> c` where any string `ab` becomes `acb` and an input string, apply the function at the same time to every (overlapping) pair of letters. Repeat this time times. Report the difference in counts between the most and least common letters in the final situation.

AoC 2021 Day 13: Foldinator

2021-12-13

Source: Transparent Origami

Part 1: Given a set of points and a sequence of ‘fold’ lines (where you either fold the bottom over the top or right over left), determine how many points exist after the first fold.

Source: Reactor Reboot

Part 1: Given a series of 3D cubes that either turn ON all or turn OFF all points in their region, calculate how many points in the region (-50..50,-50..50,-50..50) are ON at the end.

Source: Dirac Dice

Part 1: Play a simple game (describe below) with a loaded D100 (that always rolls 1, 2, 3, … 99, 100, 1, …). Return the score of the losing player times the number of times the die was rolled.

Source: Trench Map

Part 1: Given a 9->1 cellular automota update function (take the pixel and 8 surrounding pixels as a 9-bit index into the function) and a binary image, apply the function twice and count the number of ’lit’ pixels. Assume that the canvas is infinite.

Source: Snailfish

Source: Snailfish

Part 1: Given the following definition of Snailfish numbers, add a series of Snailfish numbers and return the magnitude of the result.

Source: Trick Shot

Source: Packet Decoder

Part 1: Given a recursive binary packet definition (see below), parse the given packet. Return the sum of each packet’s version.

Source: Chiton

Part 1: Given a grid of weights, find the minimum path from top left to top right. Return the total weight along that path.

Source: Extended Polymerization

Part 1: Given a complete function f(a, b) -> c where any string ab becomes acb and an input string, apply the function at the same time to every (overlapping) pair of letters. Repeat this time times. Report the difference in counts between the most and least common letters in the final situation.

Source: Transparent Origami

Part 1: Given a set of points and a sequence of ‘fold’ lines (where you either fold the bottom over the top or right over left), determine how many points exist after the first fold.

Part 1: Given a recursive binary packet definition (see below), parse the given packet. Return the sum of each packet’s `version`.