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） Dwell crops are more than simply decorative aspects in a freshwater aquarium. They lead to oxygenation, help keep h2o good quality, and supply all-natural habitats for fish. On condition that fish can't regulate t... https://pearlaquatics.my/nitrogen-cycle/