Day 15 Rambunctious Recitation
This is my attempt to solve Day 15.
15.1 Part 1
Ideally we would use a data type like a dictionary in Python for today’s problem… but there isn’t really a good option in R. Instead I will just assign a vector that will be long enough for the solution. I’m going to make an assumption that the largest number we will see will be less than the number of turns.
solve <- function(input, turns) {
turn <- numeric(turns)
# first iterate over the input
for (i in seq_along(input)) {
p <- input[[i]]
# R is 1 indexed, make it 0
turn[[p + 1]] <- i
}
# now continue for the rest of the turns
for (i in (length(input) + 1):turns) {
# find out which value was spoke
t <- turn[[p + 1]]
# update the value of the turn
turn[[p + 1]] <- i - 1
# find which word is to be spoke
p <- ifelse(t == 0, 0, i - t - 1)
}
p
}We can now test that our function works against the sample data:
## [1] TRUE## [1] TRUE## [1] TRUE## [1] TRUE## [1] TRUE## [1] TRUE## [1] TRUE## [1] TRUEWe can now run our function on the actual data:
## [1] 1696