// 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) {

HashMap<Character, Integer> map = new HashMap<Character, Integer>();

map.put('I', 1);

map.put('V', 5);

map.put('X', 10);

map.put('L', 50);

map.put('C', 100);

map.put('D', 500);

map.put('M', 1000);

int total = 0;

for(int i = 0; i < s.length() - 1; i++) {

if(map.get(s.charAt(i)) < map.get(s.charAt(i + 1))) total -= map.get(s.charAt(i));

else total += map.get(s.charAt(i));

}

total += map.get(s.charAt(s.length() - 1));

return total;

}

}