LeetCode题解：Roman to Integer

Given a roman numeral, convert it to an integer.

Input is guaranteed to be within the range from 1 to 3999.

题意：给定一个1-3999范围内的罗马数字，把它转换为整数

解决思路：按照罗马数字转换

代码：

public class Solution {
    public int romanToInt(String s) {
        int res = 0;
    for (int i = s.length() - 1; i >= 0; i--) {
        char c = s.charAt(i);
        switch (c) {
        case 'I':
            res += (res >= 5 ? -1 : 1);
            break;
        case 'V':
            res += 5;
            break;
        case 'X':
            res += 10 * (res >= 50 ? -1 : 1);
            break;
        case 'L':
            res += 50;
            break;
        case 'C':
            res += 100 * (res >= 500 ? -1 : 1);
            break;
        case 'D':
            res += 500;
            break;
        case 'M':
            res += 1000;
            break;
        }
    }
    return res;
    }
}