leetcode 13. 罗马数字转整数

class Solution {
    public int romanToInt(String s) {
        s = s.replaceAll("IV", "IIII");
        s = s.replaceAll("IX", "VIIII");
        s = s.replaceAll("XL", "XXXX");
        s = s.replaceAll("XC", "LXXXX");
        s = s.replaceAll("CD", "CCCC");
        s = s.replaceAll("CM", "DCCCC");
        char[] chars = s.toCharArray();
        int ans = 0;
        for (char c : chars) {
            ans = ans + becomeInt(c);
        }
        return ans;
    }

    public int becomeInt(char c) {
        if (c == 'I') return 1;
        if (c == 'V') return 5;
        if (c == 'X') return 10;
        if (c == 'L') return 50;
        if (c == 'C') return 100;
        if (c == 'D') return 500;
        if (c == 'M') return 1000;
        return 0;
    }
}