Roman to Integer

Author: jackzhenguo

Math/Math.Lib/RomanToInteger.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Math.Lib
+{
+	// Given a roman numeral, convert it to an integer.
+
+// Input is guaranteed to be within the range from 1 to 3999.
+    public class Solution
+    {
+		public int RomanToInt(string s) {
+				Dictionary<char, int> T = new Dictionary<char, int>{
+									   { 'I' , 1 },
+									   { 'V' , 5 },
+									   { 'X' , 10 },
+									   { 'L' , 50 },
+									   { 'C' , 100 },
+									   { 'D' , 500 },
+									   { 'M' , 1000 } 
+				};
+
+				int sum = T[s[s.Length-1]];
+				for (int i = s.Length - 2; i >= 0; --i)
+				{
+					if (T[s[i]] < T[s[i + 1]])
+					{
+						sum -= T[s[i]];
+					}
+					else
+					{
+						sum += T[s[i]];
+					}
+				}
+
+				return sum;
+		}
+    }
+
+}