Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.
1 public class Solution { 2 public int romanToInt(String s) { 3 HashMap<String, Integer> numbers = new HashMap<String, Integer>(); 4 numbers.put("M", 1000); 5 numbers.put("CM", 900); 6 numbers.put("D", 500); 7 numbers.put("CD", 400); 8 numbers.put("C", 100); 9 numbers.put("XC", 90); 10 numbers.put("L", 50); 11 numbers.put("XL", 40); 12 numbers.put("X", 10); 13 numbers.put("IX", 9); 14 numbers.put("V", 5); 15 numbers.put("IV", 4); 16 numbers.put("I", 1); 17 int result = 0; 18 for(int i = 0; i < s.length(); i ++){ 19 if(i + 1 < s.length() && numbers.containsKey(s.substring(i, i + 2))){ 20 result += numbers.get(s.substring(i, i + 2)); 21 i ++; 22 } 23 else result += numbers.get(s.substring(i,i + 1)); 24 } 25 return result; 26 } 27 }