## 一.題目描述 Given a roman numeral, convert it to an integer.? Input is guaranteed to be within the range from 1 to 3999. ## 二.題目分析 羅馬數字總結： 1~9: {“I”, “II”, “III”, “IV”, “V”, “VI”, “VII”, “VIII”, “IX”}; 10~90: {“X”, “XX”, “XXX”, “XL”, “L”, “LX”, “LXX”, “LXXX”, “XC”}; 100~900: {“C”, “CC”, “CCC”, “CD”, “D”, “DC”, “DCC”, “DCCC”, “CM”}; 1000~3000: {“M”, “MM”, “MMM”}. 關于羅馬數制可參考：[http://baike.baidu.com/view/1246899.htm](http://baike.baidu.com/view/1246899.htm) 這個問題就是輸入個阿拉伯數字，將其轉換為羅馬數字字符串。 該題可使用最簡單的操作，即取數字的低位到高位進行操作。每次取一位，取完一位則數字除10，取出的那一位數字則用羅馬數字表示出來。需要注意的是如果當前位不是原數字的各位則需要擴大10倍或者100倍等。 ## 三.示例代碼 ~~~ 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; } }; ~~~