roman to integer.java

/*Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             1000
Example 1:

Input: s = "III"
Output: 3
Explanation: III = 3. */

class Solution {
    public int romanToInt(String s) {

        Map<Character, Integer> map = new HashMap<Character, Integer>();
        int sum = 0;
        map.put('I', 1);
        map.put('V', 5);
        map.put('X', 10);
        map.put('L', 50);
        map.put('C', 100);
        map.put('D', 500);
        map.put('M', 1000);
        s = s.replace("IV", "IIII");
        s = s.replace("IX", "VIIII");
        s = s.replace("XL", "XXXX");
        s = s.replace("XC", "LXXXX");
        s = s.replace("CD", "CCCC");
        s = s.replace("CM", "DCCCC");
        for (int i = 0; i < s.length(); i++) {
            sum = sum + (map.get(s.charAt(i)));
        }
        return sum;
    }
}