leetcode Roman to Integer(Java)

题目链接：点击打开链接

类型：数学处理

解法：

public class Solution {
    public int romanToInt(String s) {
        int len = s.length();
        int[] nums = new int[len];
        
        for(int i = 0 ; i < len ; ++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 < len-1 ; ++i)
        {
        	if (nums[i] < nums[i+1])
        		sum -= nums[i];
        	else
        		sum += nums[i];
        }
        sum += nums[len-1];
        return sum;
    }
}