Integer to Roman （罗马数字变换） 【leetcode】

Integer to Roman （罗马数字转换） 【leetcode】

题目：Given an integer, convert it to a roman numeral.

Input is guaranteed to be within the range from 1 to 3999.

I = 1;
V = 5;
X = 10;
L = 50;
C = 100;
D = 500;
M = 1000;

其中每两个阶段的之间有一个减法的表示，比如900=CM， C写在M前面表示M-C。

范围给到3999，感觉情况不多直接打表其实更快，用代码判断表示估计比较繁琐。

然后就是贪心的做法，每次选择能表示的最大值，把对应的字符串连起来。 

class Solution {public:    string intToRoman(int num) {        string str;          string symbol[]={"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"};          int value[]=    {1000,900,500,400, 100, 90,  50, 40,  10, 9,   5,  4,   1};         for(int i=0;num!=0;++i)        {            while(num>=value[i])            {                num-=value[i];                str+=symbol[i];            }        }        return str;    }};