AoC 2021 Day 16: Depacketinator

Part 1: Start with n stacks of different sizes. Take the largest block and distribute its items starting with n+1 and looping around. How many iterations of this does it take before you see a state you’ve seen before?

AoC 2017 Day 3: Spiraly

2017-12-03

Source: Spiral Memory

Part 1: Create a grid in a spiral pattern like so:

17 16 15 14 13 18 5 4 3 12 19 6 1 2 11 20 7 8 9 10 21 22 23—> …

AoC 2016 Day 20: Filter Table

2016-12-20

Source: Firewall Rules

Part 1: Given a list of integer ranges (a la 5-8), what is the first value not in any given range?

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: 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.

Source: Smoke Basin

Part 1: Given a heightmap, find all local minimums. Return the sum of (minimum height + 1) for each local minimum.

Source: Digital Plumber

Source: Recursive Circus

Source: Memory Reallocation

Source: Spiral Memory

Source: Firewall Rules

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.