Cumulative sum for positive numbers only

Question

I have this vector :

x = c(1,1,1,1,1,0,1,0,0,0,1,1)

And I want to do a cumulative sum for the positive numbers only. I should have the fol

Answer 1

One option is

x1 <- inverse.rle(within.list(rle(x), values[!!values] <- 
                  (cumsum(values))[!!values]))
x[x1!=0] <- ave(x[x1!=0], x1[x1!=0], FUN=seq_along)
x
#[1] 1 2 3 4 5 0 1 0 0 0 1 2

Or a one-line code would be

 x[x>0] <-  with(rle(x), sequence(lengths[!!values]))
 x
 #[1] 1 2 3 4 5 0 1 0 0 0 1 2