School of Mathematics, Shandong University, Jinan, China.|Department of Bioinformatics and Genomics, College of Computing and Informatics, The University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, USA.|College of Computer and Information Engineering, Tianjin Normal University, Tianjin, China.|School of Mathematics, Shandong University, Jinan, China.|Department of Bioinformatics and Genomics, College of Computing and Informatics, The University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, USA.