Department of Computer Science, Stony Brook University Stony Brook, New York, NY 11794-2424, USA.|Department of Computer Science, Stony Brook University Stony Brook, New York, NY 11794-2424, USA.|Department of Computer Science, Stony Brook University Stony Brook, New York, NY 11794-2424, USA.|Department of Computer Science, Stony Brook University Stony Brook, New York, NY 11794-2424, USA.