Java: public static int parseRoman(String romanChars) { int result = 0; HashMap romanMap = new HashMap(); romanMap.put("I", 1); romanMap.put("V", 5); romanMap.put("X", 10); romanMap.put("L", 50); romanMap.put("C", 100); romanMap.put("D", 500); romanMap.put("M", 1000); int curChar = 0, prevChar = 0; for (int i = romanChars.length() - 1; i >= 0; i--) { curChar = romanMap.get(String.valueOf(romanChars.charAt(i))); if (i > 0) prevChar = romanMap.get(String.valueOf(romanChars.charAt(i-1))); else prevChar = 0; if (curChar <= prevChar) result += curChar; else { result += (curChar - prevChar); i--; } } return result; }