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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Source: Treetop Tree House

Part 1

Given a grid of numbers, count how many of these numbers have a direct path in any cardinal direction to the edge of the grid.

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Source: No Space Left On Device

Part 1

Give the output of a very simple shell with only the commands cd and ls (the output of which is either "dir" name for directories or size name for files), find the largest directory (disk usage calculated recursively) with a size no greater than 100,000.

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Source: Tuning Trouble

Part 1

Given input as a list of characters, find the index of the first sliding window (size 4) where all of the characters are distinct.

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Source: Supply Stacks

Part 1

Given a list of stacks of syntax 1 and instructions in the form syntax 2, apply each instruction to pop qty items from the stack src and put them on dst one at a time.

Syntax 1: Stacks

    [D]    
[N] [C]    
[Z] [M] [P]
 1   2   3 

Syntax 2: Instructions

move 1 from 2 to 1
move 3 from 1 to 3
move 2 from 2 to 1
move 1 from 1 to 2

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Source: Camp Cleanup

Part 1

Given a list of pairs of spans (of the form a-b,x-y) count how many spans have one span entirely contained within the other.

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Source: Rucksack Reorganization

Part 1

Take a list of characters. For each line, split the line exactly in half and find the one character that’s in both halves. Assign a-z to values 1-26 and A-Z to 27-52. Sum these values.

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Source: Rock Paper Scissors

Part 1

Given a list of Rock Paper Scissors matches with A,B,C or X,Y,Z corresponding to those plays and scoring 1,2,3 points for your play plus 0,3,6 for a loss, draw, or win, what is your total score.

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Source: Calorie Counting

Part 1

Given multiple lists of numbers, find the list with the largest sum.

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Let’s do this thing!

I’m going to try Rust this time, since it’s 1) awesome 2) fast and 3) crazy. :D

Let’s see how it goes!

If you’d like to see the full form of any particular solution, you can do so on GitHub (including previous years and possibly some I haven’t written up yet): jpverkamp/advent-of-code

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