One entity in more than one category, count half in each category

I have stumbled onto a problem I haven't been able to solve. I have a person in two different categories, and I need to count them as 0.5 in each category.

Here is the sample data:

Notice that ID Number 18 has a slash indicating that the two departments. I need the output to read as follows.

My first thought was to split the DEPT column, but I am not sure where to go from there since the two rows are identical. My code is as follows. Any suggestions?

Grad_Applied_Formatted1 <-  Grad_AppAccMat %>%
separate_wider_delim(DEPT,"/", names= c("DEPT1","DEPT2"), 
too_few = "align_start",cols_remove = F)

You can use tidyr::separate_longer_delim() and then remove duplicated rows.

df <- data.frame(
  ID = c(17, 18, 18),
  DEPT = c("VZX", "EPI/ENH", "EPI/ENH"),
  COUNT = c(1, 0.5, 0.5)
)

df %>%
  tidyr::separate_longer_delim(DEPT, delim = '/') %>%
  dplyr::distinct()

#   ID DEPT COUNT
# 1 17  VZX   1.0
# 2 18  EPI   0.5
# 3 18  ENH   0.5