A Coverage and Connectivity of WSN in 3D Surface Using Sailfish Optimizer Thi Kien Dao1, Shi Jie Jiang1, Xiao Rong Ji1, Truong Giang Ngo2*, Trong The Nguyen3, Huu Trung Tran3 1Fujian Provincial Key Laboratory of Big Data Mining and Applications, Fujian University of Technology, Fuzhou, China; 2Faculty of Computer Science and Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam; 3Department of Information Technology, Haiphong University of Manage and Technology, Haiphong, Vietnam[.]