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

LeetCode-Integer to Roman

C++:
class Solution {
public:
    string intToRoman(int num) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function    
        const static char *Roman="IVXLCDM";
        string ret;
        for(int base=0;num;num /=10,base=base+2){
            int cur=num%10;
            switch(cur){
                case 1:case 2:case 3:
                    ret =string(cur,Roman[base])+ret;
                    break;
                case 4:
                    ret =Roman[base+1]+ret;
                    ret =Roman[base]+ret;
                    break;
                case 5:
                    ret =Roman[base+1]+ret;
                    break;
                case 6:case 7:case 8:
                    ret =string(cur-5,Roman[base])+ret;
                    ret =Roman[base+1]+ret;
                    break;
                case 9:
                    ret =Roman[base+2]+ret;
                    ret =Roman[base]+ret;
                    break;
                default:
                    break;
            }
        }
        return ret;
    }
};
Java:
public class Solution {
    public String intToRoman(int num) {
        // Start typing your Java solution below
        // DO NOT write main() function
        char[] Roman="IVXLCDM".toCharArray();
        StringBuilder ret=new StringBuilder();
        for(int base=0;num>0;num /=10,base=base+2){
            int cur=num%10;
            switch(cur){
                case 1:case 2:case 3:
                    for(int i=0;i<cur;i++) ret.insert(0,Roman[base]);
                    break;
                case 4:
                    ret.insert(0,Roman[base+1]);
                    ret.insert(0,Roman[base]);
                    break;
                case 5:
                    ret.insert(0,Roman[base+1]);
                    break;
                case 6:case 7:case 8:
                    for(int i=0;i<cur-5;i++) ret.insert(0,Roman[base]);
                    ret.insert(0,Roman[base+1]);
                    break;
                case 9:
                    ret.insert(0,Roman[base+2]);
                    ret.insert(0,Roman[base]);
                    break;
                default:
                    break;
            }
        }
        return ret.toString();
    }
}