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 can't connect with the server for this app or Web-site at the moment. There may be an excessive amount site visitors or a configuration mistake. Try all over again afterwards, or Get hold of the app or Internet... https://pearlaquatics.my/author/sushant/page/3/