I. Introduction
Nowadays, UAVs play increasingly important roles in many real-life applications such as real-time monitoring, wireless coverage, searching and rescuing [1]–[3]. As one of the important foundations of UAV applications, Coverage Path Planning (CPP) that aims to find a pathway or pathways to cover the targets or regions of interest, has received significant research attention. The traditional research on CPP can be divided into three groups: multiple UAVs traverse the interior of a single region, a single UAV traverses multiple scattered regions, and multiple UAVs traverse multiple scattered regions.