12. Integer to Roman

class Solution {
public:
    string intToRoman(int num)
    {
    	int nums[4]={1000,100,10,1};
    	char big[4]={'M','C','X','I'};
    	char small[4]={' ','D','L','V'};

    	string ans;
    	for(int i=0;i<4;i++)
    	{
    		int div=num/nums[i];
    		if(div==9)
    		{
    			ans= ans+ big[i]+big[i-1];
    		}
    		else
    			if(div>=5&&div<=8)
    			{
    				ans = ans + small[i];
    				for(int j = 0;j<div-5;j++)
    					ans += big[i];
    			}
    			else
    				if(div>=1&&div<=3)
    				{
    					for(int j =0 ;j<div;j++)
    						ans += big[i];
    				}
    				else
    					if(div==4)
    					{
    						ans = ans + big[i] + small[i];
    					}
    		num%=nums[i];

    	}
    	return ans;
    }
};