Solution to Devmates.co Roman Numerals

gistfile1.txt

private static final Map<Character, Integer> numeralMap = new HashMap<>();
    static {
        numeralMap.put('I', 1);
        numeralMap.put('V', 5);
        numeralMap.put('X', 10);
        numeralMap.put('L', 50);
        numeralMap.put('C', 100);
        numeralMap.put('D', 500);
        numeralMap.put('M', 1000);
    }

    public int solve(String input) {
        int sum = 0;
        char[] chars = input.toCharArray();
        int top = 0;
        for (int i = chars.length - 1; i >= 0; i--) {
            int v = numeralMap.get(chars[i]);
            if (v < top) {
                sum -= v;
                top = 0;
            }
            else {
                sum += v;
                top = v;
            }
        }

        return sum;
    }