2021 Day 16

Author

Nathan Moore

— Day 16: Packet Decoder —

As you leave the cave and reach open waters, you receive a transmission from the Elves back on the ship.

The transmission was sent using the Buoyancy Interchange Transmission System (BITS), a method of packing numeric expressions into a binary sequence.

Decode the structure of your hexadecimal-encoded BITS transmission; what do you get if you add up the version numbers in all packets?

library(tidyverse)
library(BMS)

my_file <- here::here("2021", "data-2021-16.txt")
x <- readLines(my_file)
y = strsplit(x, "")

Loops with lots of rules? Wish me luck.

z = c()

for (e in y) {
    z = c(z, hex2bin(as.character(e)))
}

z[1:100]

  [1] 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 1 1 1 1 0
 [38] 0 0 0 1 0 0 1 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1 0 1 0 0 0 0 1 1
 [75] 1 1 0 0 0 0 1 0 0 1 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 1

Paste part two here