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） Reside plants are more than just attractive features inside of a freshwater aquarium. They add to oxygenation, enable retain drinking water good quality, and provide organic habitats for fish. 三個月 返 回 , 17/1... https://pearlaquatics.my/category/pearl-aquatics/page/3/