AoC 2021 Day 17: Pew-Pewinator

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 14: Polymerizationinator

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 12: Submarine Spider

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

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

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.