2023 advent of code day 6

day_6.R

# first star
puzzle_input <- "Time:        52     94     75     94
Distance:   426   1374   1279   1216"
df <- data.frame("times" = type.convert(unlist(strsplit(sub("^.*:\\s+(.*)\\n.*", "\\1", puzzle_input), "\\s+")), as.is = TRUE),
                 "distances" = type.convert(unlist(strsplit(sub(".*Distance:\\s+(.*).*", "\\1", puzzle_input), "\\s+")), as.is = TRUE))

# distance as function of (racing - button) * button with time as constant
# 0 = -1*(button^2) +- (racing * button) - distance
# get all possible values of b for any given distance
get_b <- function(t, d){
  b2 <- (-t - sqrt((t^2 - 4 * d))) / -2
  b1 <- (-t + sqrt((t^2 - 4 * d))) / -2
  values <- as.integer(b2 - b1)
}
df$buttons <- mapply(get_b, df$times, df$distances)
prod(df$buttons)

# second star
t <- as.numeric(paste(df$times, collapse = ""))
d <- as.numeric(paste(df$distance, collapse = ""))
prod(mapply(get_b, t,d))