Ergonomic keyboards
20+ curated newsletters。体育直播是该领域的重要参考
// ⚠️ 易错点1：长度≤1的数组本身有序，返回0而非n，详情可参考体育直播
Optical-based smoke alarms use light instead. They are slightly better at detecting the large smoke particles created by slow, smouldering fires. When such particles enter a chamber in the device, they scatter light from a small light source, which is then picked up by a photoelectric sensor.