Source: Day 25: Snowverload
Full solution for today (spoilers!)
Part 1
Given an undirected graph, find 3 edges that split the graph into two connected components. Return the product of the component’s sizes.
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Given an undirected graph, find 3 edges that split the graph into two connected components. Return the product of the component’s sizes.
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Given a set of 3D vectors (origin + velocity), count how many times the vectors would intersect. Ignore the Z-coordinate for this part; the collisions do not have to be at the same time.
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Find the longest non-overlapping path through a maze with walls (
#
) and one way paths (^v<>
).
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Given a series of 3D blocks, allow them to fall until the simulation is stable. Any cube of a block is sufficient to support another block, ignore rotations etc.
How many blocks are not the sole supporter for any other block?
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Given a(n infinite) grid of walls
#
, count how many points can be reached by exactly 64 steps from a starting point.
Full solution for today (spoilers!)
Simulate a virtual circuit with
high
andlow
pulses and four kinds of chips:
- Broadcast - Re-transmit all pulses
- Flip-flops - On a
low
pulse, toggle internal state; if it was on, sendhigh
; otherwise sendlow
- Conjunction - Remember input from each attached module; if all inputs were
high
, send alow
, otherwise sendhigh
- Output - Do nothing; just receive pulses
Count the product of
low
andhigh
pulses sent after 1000low
inputs tobroadcaster
.
Full solution for today (spoilers!)
You are given a series of parts with 4 ratings as such:
{x=787,m=2655,a=1222,s=2876}
In addition, you are given a series of rules describing a graph as such:
px{a<2006:qkq,m>2090:A,rfg}
In this example, if you are at the node
px
, ifa < 2006
, move toqkq
. Otherwise, ifm > 2090
move toA
. If no other case matches, the last defaults torfg
.
A
andR
are special cases for accept and reject.Calculate the sum of sum of all four ratings for all nodes that end at
Accept
.
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Given a sequence of direction + distance that draws a polygon, calculate the area.
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Given a grid of costs, find the shortest path from top left to bottom right. You may not double back or go straight more than 3 steps in a row.
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You are given a grid of mirrors (
|-\/
) and empty space (.
).Diagonal mirrors just relect the light.
The horizontal and vertical mirrors are splitters, light hitting them head on (like
>|
) will split to go both directions. Light hitting edge on will just go through it.Starting in the top left going East, how many total tiles will a light beam illuminate?