摘要： 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

摘要： Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpo 阅读全文

摘要： Implement regular expression matching with support for '.' and '*'. 思路：在出现*的时候，因为可能出现0，1，2，...次，所以要使用到带回溯的递归 阅读全文