Department of Computer Science, University of California, Berkeley, 387 Soda Hall, Berkeley, 94720, USA.|Department of Computer Science, University of Michigan, 486 Vassar Avenue, Berkeley, CA, 94708, USA.|Innovative Genomics Initiative, University of California, Berkeley, 188 Li Ka Shing Center, Berkeley, CA, 94720, USA.|Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland, Dunhagi 5, 107, Reykjavík, Iceland.|Department of Computer Science, University of California, Berkeley, 387 Soda Hall, Berkeley, 94720, USA. lpachter@math.berkeley.edu.