Source: Digital Plumber

Part 1: A network of nodes is defined by a list of lines formatted as such:

2 <-> 0, 3, 4

In this case, node 2 is connected to 0, 3, and 4 and vice versa.

How many nodes are in the group that contains the node 0?

read more...

Source: Hex Ed¹

Part 1: Work on a hex grid:

  \ n  /
nw +--+ ne
  /    \
-+      +-
  \    /
sw +--+ se
  / s  \

Given a series of steps (n, se, ne) etc, how many steps away from the origin do you end up?

read more...

Source: Knot Hash

Part 1: Starting with a list of the numbers from 1 to n and a list of lengths (as input):

1. Initialize current_position and skip_size to 0
2. For each length element in the lengths list:
3. Reverse the first length elements of the list (starting at current_position)
4. Move forward by length plus skip_size
5. Increment skip_size by 1

After applying the above algorithm, what is the product of the first two elements in the list (from the original first position, not the current_position)?

read more...

Source: Stream Processing

Part 1: An input stream can contain:

• groups are delimited by { and }, groups are nestable and may contain garbage or data (objects within a group are comma delimited)
• garbage is delimited by < and >, groups cannot be nested within garbage, a ! within garbage is an escape character: !> does not end a garbage segment

The score of a single group is equal to how many times it is nested (the innermost group of {{{}}} has score 3).

The score of a stream is the sum of the scores of all groups in that stream.

What is the total score of your input?

read more...

Source: I Heard You Like Registers¹

Part 1: Given a set of registers initialized to 0, interpret a series of instruction of the form:

• {register} (inc|dec) {number|register} if {number|register} (<|<=|=|!=|=>|>) {number|register}

What is the largest value in any register?

read more...

Source: Recursive Circus

Part 1: A tree is defined as such:

• node (weight) -> child1, child2, ...
• node (weight)

Where a node always has a weight, but may or may not have child nodes.

What is the name of the root node of the tree (the node without a parent)?

read more...

Source: Memory Reallocation

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?

read more...

Source: A Maze of Twisty Trampolines, All Alike¹

Part 1: Interpret a program made entirely of jump instructions: each instruction is how many steps to jump. Any time you use an instruction to jump, increase the value of that jump by 1 for next time. How many total steps does it take to escape (jump out of bounds)?

read more...

Source: High-Entropy Passphrases

Part 1: Given a list of passphrases, count how many contain no duplicate words.

read more...

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---> ...

Given a specific index, what is the Manhattan Distance from that point to the origin (1)?

read more...