using System;

​

namespace C_ArraysCollections

{

    class RomanNumeral

    {

        private static Dictionary<char, int> map = new Dictionary<char, int>()

        {

            {'I', 1},

            {'V', 5},

            {'X', 10},

            {'L', 50},

            {'C', 100},

            {'D', 500},

            {'M', 1000},

        }

        public static int Parse(string roman)

        {

            int result = 0;

            for(int i = 0; i<roman.Length; i++)

            {

                if(i+1 < roman.Length && IsSubtractive(roman[i], roman[i +1]))

                {

                    result -= map[roman[i]];

                }

                else

                {

                    result += map[roman[i]];

                }

            }

            return result;

        }

        private static bool IsSubtractive(char c1, char c2)

        {

            return map[c1] < map[c2];

        }

    }

}