13. Roman to Integer

13. Roman to Integer

Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

class Solution {
      public int romanToInt(String s) {
            char [] chars=s.toCharArray();
            int result=Roman(chars[0]);
            for(int i=0;i<s.length()-1;i++){
                result=Calculate(Roman(chars[i]),Roman(chars[i+1]),result);
            }
            return result;
        }

        int Roman(char x){
            int fanhui;
            switch (x)
            {
                case 'I':
                    fanhui=1;
                    break;
                case 'V':
                    fanhui=5;
                    break;
                case 'X':
                    fanhui=10;
                    break;
                case 'L':
                    fanhui=50;
                    break;
                case 'C':
                    fanhui=100;
                    break;
                case 'D':
                    fanhui=500;
                    break;
                case 'M':
                    fanhui=1000;
                    break;
                default:
                    return 0;               
            }
            return fanhui;
        }

        int Calculate(int left,int right,int result){
            if(left>=right)
                    return result+right;
            else
                return result+right-2*left;
        }
}