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key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） Allow one other champion the remainder of your aquatic realm, removing gravel challenges and preserving the pristine perfection of one's acrylic haven. Dive into your TRUVU approach—safeguard your tank, banish algae, ... https://pearlaquatics.my/how-to-take-care-of-your-flowerhorn-fish/