Contents

/*
 * 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;
 */
```s

## 题意：
    将数字转换为罗马数字

- 按罗马数字的规则来模拟

```java
//这些数字是特征数字
1000, 900, 500, 400,  
100, 90, 50, 40,  
10, 9, 5, 4,  
1

(1,"I")   
(2,"II")  
(3,"III")  
(4,"IV")  
(5,"V")   
(6,"VI")  
(7,"VII")  
(8,"VIII")  
(9,"IX")  
(10,"X")  
(20,"XX")  
(30,"XXX")  
(40,"XL")  
(50,"L")  
(60,"LX")  
(70,"LXX")  
(80,"LXXX")  
(90,"XC")  
(100,"C")  
(200,"CC")  
(300,"CCC")  
(400,"CD")  
(500,"D")  
(600,"DC")  
(700,"DCC")  
(800,"DCCC")  
(900,"CM")  
(1000,"M")  
(2000,"MM")  
(3000,"MMM")

public class Solution {  
    private int[] val = {  
            1000, 900, 500, 400,  
            100, 90, 50, 40,  
            10, 9, 5, 4,  
            1  
    };  
    private String[] syb = new String[] {  
            "M", "CM", "D", "CD",  
            "C", "XC", "L", "XL",  
            "X", "IX", "V", "IV",  
            "I"  
    };  
  
  
    public String intToRoman(int num) {  
        StringBuilder roman = new StringBuilder();  
        int i = 0, k;  
        while (num > 0) {  
            k = num / val[i];  
            while (k-- > 0) {  
                roman.append(syb[i]);  
                num -= val[i];  
            }  
            i++;  
        }  
        return roman.toString();  
    }  
}