摘要：题目： Given two numbers represented as strings, return multiplication of the numbers as a string. Note: The numbers can be arbitrarily large and are non 阅读全文

摘要：题目：Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array w 阅读全文

摘要：题目： Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would hav 阅读全文