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） Stay plants tend to be more than just attractive components in the freshwater aquarium. They add to oxygenation, assistance preserve drinking water high-quality, and provide natural habitats for fish. 回復/查看 排序: ... https://pearlaquatics.my/why-should-you-focus-on-pond-cleaning/