12 Integer to Roman 4eb642456f43406d954901d58cf68c05.md

12. Integer to Roman

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import java.util.Enumeration;
import java.util.Hashtable;

class Solution {
     public static String intToRoman(int num)
    {
        StringBuilder s = new StringBuilder();

        Hashtable<Integer , String > list = new Hashtable<>();
        list.put(1 , "I");
        list.put(4 , "IV");
        list.put(5 , "V");
        list.put(9 , "IX");
        list.put(10 , "X");
        list.put(40 , "XL");
        list.put(50 , "L");
        list.put(90 , "XC");
        list.put(100 , "C");
        list.put(400 , "CD");
        list.put(500 , "D");
        list.put(900 , "CM");
        list.put(1000 , "M");
        
        while (num > 0)
        {
            int maxkey = getMaxKey(list , num);
            s.append(list.get(maxkey));
            num -= maxkey;
        }
        return s.toString();
    }

    public static int getMaxKey(Hashtable list , int target)
    {
        int maxKey = -1;

        Enumeration<Integer> keys = list.keys();
        while (keys.hasMoreElements()) {
            int key = keys.nextElement();
            if (key <= target && key > maxKey) {
                maxKey = key;
            }
        }
        return maxKey;
    }
}

class Solution {
public String intToRoman(int num)
 {
        String ones[] = {"","I","II","III","IV","V","VI","VII","VIII","IX"};
        String tens[] = {"","X","XX","XXX","XL","L","LX","LXX","LXXX","XC"};
        String hrns[] = {"","C","CC","CCC","CD","D","DC","DCC","DCCC","CM"};
         String ths[] = {"","M","MM","MMM"};
        
        StringBuilder ans = new StringBuilder();

        ans.append(ths[num / 1000]);
        ans.append(hrns[(num % 1000) / 100]);
        ans.append(tens[(num % 100) / 10]);
        ans.append(ones[num % 10]);

        return ans.toString();   
 }
}