$(20$ points$).$ Redefine the following function positions:

positions :: Eq a $=>$ a $->[$a$]->[$Int$]$

positions x xs $=[$i $|($x$,$i$)<-$ zip xs $[0..],$ x $==$ x$]$

using the following function find:

find :: Eq a $=>$ a $->[($a$,$b$)]->[$b$]$

find k t $=[$v $|($k$,$v$)<-$ t$,$ k $==$ k$]$

Hint: the simplest solution will still involve zip, but it need not be in a list comprehension anymore,

due to the usage of find.