说明：  This work proposes a new meta-heuristic called Grey Wolf Optimizer (GWO) inspired by grey wolves (Canis lupus). The GWO algorithm mimics the leadership hierarchy and hunting mechanism of grey wolves in nature. Four types of grey wolves such as alpha, beta, delta, and omega are employed for sim-ulating the leadership hierarchy. In addition, the three main steps of hunting, searching for prey, encir-cling prey, and attacking prey, are implemented.