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essential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) Regular screening and adjustment of salinity degrees are crucial to the properly-getting of your maritime lifestyle. Normally make use of a dependable hydrometer or refractometer to evaluate salinity accurately.... https://pearlaquatics.my/tips-to-maintain-your-fish-pond/