再用n2的时间（两重循环）枚举d-c，并将b-c的值作为键，在Hash数组中查找是否存在。如果能找到crucial相同的node点，则找到了一组满足 d-c = a+b的值。（注意检查a b c d 四个数不重复） We will not connect to the server for this app or Web-site at the moment. There could possibly be excessive traffic or simply a configuration error. Consider again later on, or Call the app or website proprietor. ... https://pearlaquatics.my/7-tips-to-control-and-prevent-algae/