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） Stay plants tend to be more than just decorative aspects inside of a freshwater aquarium. They add to oxygenation, aid preserve h2o high-quality, and provide pure habitats for fish. अन्‍य डेटा गोपनीयता संबंधी तौर-... https://pearlaquatics.my/product/ocean-free-new-water-guard/