RoAlgo Educational Round #2 | duplicare

Task

You are given an integer $n$, with at most $4$ digits. Implement the function duplicare, which gets as a parameter an integer $n$ and returns $d$, the number obtained by writing each odd digit twice, or $-1$, if there was no such digit.

The proposed solution will only contain the definition of the required function. The occurence of other instructions can lead to errors which can lead to your solution obtaining a lower score.

Example

As an example, duplicare($1032$) = $110332$, but duplicare($4084$) = $-1$.