摘要：
Given an integer, convert it to a roman numeral. Input is guaranteed to be within the range from 1 to 3999. 解释： 罗马数字采用七个罗马字母作数字、即Ⅰ（1）、X（10）、C（100）、M（1 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