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） Reside plants are more than just decorative things inside of a freshwater aquarium. They add to oxygenation, help preserve water top quality, and provide all-natural habitats for fish. गड़बड़ियां ठीक की गईं, परफ़ॉर्मे... https://pearlaquatics.my/ideas-for-fish-pond-refurbishment/