Points were taken off as follows:

For incorrect answers:

   -100 (no credit) if code doesn't assemble or has runtime exception for starter code.
        in this case, contact the TA or instructor.

   -10 not correctly detect the first or last element (particular K values)

   -10  failing the base case

   -50  not computing the correct result in any case (which replaces the
     above penalties)

   -10  program not terminating for some tested case  (but not most)
  
   -10  program generating runtime error for some tested case (but not most)

For other mistakes 

-10  using "list" and "partitionedlist" labels inside the function
     (see A3 discussion board for why this is incorrect -- there were 
      a few posts about it e.g. one with subject "list & partitionedList in findRankK")

-20  implementing a non-recursive version in the case you directly
     converted the recursive algorithm given in the PDF to a non-recursive
     version.    

-10  additional penalty for the previous mistake, if you used the stack 
     within your iterative since this is unnecessary and illustrates 
     that you don't know understand what the stack is for

-70  for implementing a non-recursive version of the algorithm which deviates
     signifiantly from the algorithm given in the PDF,  for example,  sort 
     the elements and then find the kth in a sorted list.

-5  saving registers that are not used in the function to stack
     (This one was only to get your attention so you realize that it is wrong)

-5  not following submission requirements e.g.  submitting starter code

-5   no comments (or useless comments)
 
Some students initialized $a registers inside the findRankK function  
(This makes no sense so the amount taken off will interact with other 
penalties.)