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vital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 rest of your aquatic realm, removing gravel threats and preserving the pristine perfection of one's acrylic haven. Dive into the TRUVU strategy—safeguard your tank, banish algae, and enj... https://pearlaquatics.my/4-things-new-aquarists-keeping-flowerhorn-fish-should-maintain/