OK, mine is the result of running this pseudocode:

   # Label all streets as much as possible
   for (each street on screen):
     while (that street has room for a label): # (even if already labeled)
       put a label on that street              # i.e. an additional one

yours is:

   # Try to label unlabeled streets
   for (each street on screen)
     if (no label on screen for that street): # if unlabeled
       if (street has room for a label):      # ...can we fix?
         put a label on that street           # ...then fix

(I would usually write this with an && rather than nested if's but I know mobile makes you scroll sideways)

As a followup, could you please define "street has room for a label"? When do you consider that a street has room for a label?