进阶之路

摘要： 3Sum Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. 阅读全文

摘要： Integer to Roman Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 阅读全文