# [R], 58 bytes <!-- language-all: lang-r --> function(v,x){d=diff(c(0,which(v==x))) sequence(d,d-1,-1)} **output** f(int, 0) # [1] 2 1 0 2 1 0 0 f(int, 1) # [1] 0 0 f(int, 2) # [1] 4 3 2 1 0 2 1 0 f(int, 3) # integer(0) f(char, "A") # [1] 0 2 1 0 0 f(char, "B") # [1] 1 0 f(char, "C") # [1] 2 1 0 f(char, "D") # integer(0) Works for R >= 4.0.0. [R]: https://www.r-project.org/