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.

AoC 2021 Day 12: Submarine Spider

2021-12-12

Source: Passage Pathing

Part 1: Given a list of edges in a bi-directional graph, count the number of paths from `start` to `end` such that nodes named with lowercase letters are visited once, and nodes with uppercase letters can be visited any number of times.

AoC 2021 Day 11: Octopus Flashinator

2021-12-11

Source: Dumbo Octopus

Part 1: Simulate a grid of numbers such that on each tick: advance all numbers by 1, any number that increases over 9 will ‘flash’ and add 1 to all neighbors (recursively, but each cell can only flash once) and then reset to 0. Count the number of flashes in the first 100 ticks.

AoC 2021 Day 10: Chunkinator

2021-12-10

Source: Syntax Scoring

Part 1: Given a sequence of () [] {}, and <> with nesting allowed. Find the first syntax error (where the wrong closing symbol is used). Scoring 3, 57, 1197, and 25137 respectively for each error, calculate the total error score.

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.

Source: Passage Pathing

Part 1: Given a list of edges in a bi-directional graph, count the number of paths from start to end such that nodes named with lowercase letters are visited once, and nodes with uppercase letters can be visited any number of times.

Source: Dumbo Octopus

Part 1: Simulate a grid of numbers such that on each tick: advance all numbers by 1, any number that increases over 9 will ‘flash’ and add 1 to all neighbors (recursively, but each cell can only flash once) and then reset to 0. Count the number of flashes in the first 100 ticks.

Source: Syntax Scoring

Part 1: Given a sequence of () [] {}, and <> with nesting allowed. Find the first syntax error (where the wrong closing symbol is used). Scoring 3, 57, 1197, and 25137 respectively for each error, calculate the total error score.

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

Part 1: Given a list of edges in a bi-directional graph, count the number of paths from `start` to `end` such that nodes named with lowercase letters are visited once, and nodes with uppercase letters can be visited any number of times.