Given an integer, convert it to a roman numeral.
Input is guaranteed to be within the range from 1 to 3999.
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题目

给定一个整数，将其转换成罗马数字。

返回的结果要求在1-3999的范围内。

说明什么是 罗马数字?
https://en.wikipedia.org/wiki/Roman_numerals
https://zh.wikipedia.org/wiki/%E7%BD%97%E9%A9%AC%E6%95%B0%E5%AD%97
http://baike.baidu.com/view/42061.htm

样例4
-> IV

12
-> XII

21
-> XXI

99
-> XCIX

更多案例，请戳 http://literacy.kent.edu/Minigrants/Cinci/romanchart.htm

分析

循环判断即可

代码

public class Solution {
    /**
     * @param n The integer
     * @return Roman representation
     */
    public String intToRoman(int num) {
        if(num <= 0)
            return "";
        
        String[] symbols = {"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};
        int[] nums = {1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
        
        int digit = 0;
        StringBuilder sb = new StringBuilder();
        while(num > 0) {
            int times = num/nums[digit];
            num = num-times*nums[digit];
            
            for(;times>0;times--) {
                sb.append(symbols[digit]);
            }
            digit++;
        }
        return sb.toString();
    }
}