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vital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） Normal tests and adjustment of salinity levels are critical with the nicely-currently being within your marine existence. Generally utilize a reputable hydrometer or refractometer to evaluate salinity properly. 回復... https://pearlaquatics.my/how-to-build-a-fish-pond-or-a-garden-pond-at-home/