[leetcode]13. Roman to Integer(Java)

https://leetcode.com/problems/roman-to-integer/#/description

Given a roman numeral, convert it to an integer.
Input is guaranteed to be within the range from 1 to 3999.

package go.jacob.day716;

public class Demo2 {
public int romanToInt(String s) {
int nums[] = new int[s.length()];
for (int i = 0; i < s.length(); i++) {
switch (s.charAt(i)) {
case 'M':
nums[i] = 1000;
break;
case 'D':
nums[i] = 500;
break;
case 'C':
nums[i] = 100;
break;
case 'L':
nums[i] = 50;
break;
case 'X':
nums[i] = 10;
break;
case 'V':
nums[i] = 5;
break;
case 'I':
nums[i] = 1;
break;
}
}
int sum = 0;
for (int i = 0; i < nums.length - 1; i++) {
if (nums[i] < nums[i + 1])
sum -= nums[i];
else
sum += nums[i];
}
return sum + nums[nums.length - 1];
}
}