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important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） All trademarks are either the house of Central Back garden & Pet Organization, its subsidiaries, divisions, affiliated and/or linked providers or the property of their respective proprietors. अन्‍य डेटा गोपनीयता... https://pearlaquatics.my/tag/fish-pond/