Jumped Elements X20478

Write a function @jumps(a,k)@ that receives a list of strictly positive integers $a$ and an integer $k$, and returns the list of jumped elements in $a$ starting from position $k$.

The list of jumped elements in list $a$ starting from position $k$ is defined as the list formed by element a[k] followed by the list of jumped elements starting from position k+a[k]. If $k$ is larger than the size of $a$, the result is an empty list.

For instance, given the list $a=$[2 1 3 5 7 2 9 5 2 4 8] and starting position $k=2$, the resulting list is [3 2 5]. That is, we start at position $k=2$ finding element $a[k]=3$. We advance $3$ positions and reach element $a[k]=2$. We thus advance $2$ more positions and land on element $a[k]=5$. We try to advance $5$ positions but reach the end of the list, so we stop.

Sample session

Observations

If you want to test your program locally, remember to include the following lines at the end of the file:

if __name__ == "__main__":
   import doctest
   doctest.testmod(verbose=True)