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 another champion the remainder of your aquatic realm, doing away with gravel threats and preserving the pristine perfection within your acrylic haven. Dive in the TRUVU strategy—safeguard your tank, banish algae... https://pearlaquatics.my/product/sobo5x2x3/