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） Reside vegetation are more than just decorative features in the freshwater aquarium. They lead to oxygenation, help retain h2o quality, and supply natural habitats for fish. I didn't choose to go but my father wen... https://pearlaquatics.my/product/sobo-mini-ac-dc-air-pump-sb-568/