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critical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） Reside plants tend to be more than simply attractive elements within a freshwater aquarium. They contribute to oxygenation, assist retain h2o excellent, and supply normal habitats for fish. 回復/查看 查看 時間: ... https://pearlaquatics.my/4-things-to-maintain-when-having-an-aquarium/