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） Live plants are more than just decorative factors inside of a freshwater aquarium. They add to oxygenation, enable maintain drinking water high-quality, and supply purely natural habitats for fish. i did not desi... https://pearlaquatics.my/author/sushant/