13. Roman to Integer

题目：

Given a roman numeral, convert it to an integer.

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

链接：https://leetcode.com/problems/roman-to-integer/

2/9/2017

主要问题在不熟悉Java，举例：

HashMap<char, integer> --> HashMap<Character, Integer>,

String.length(), 与array的length不同

String.charAt()

public class Solution {
    public int romanToInt(String s) {
        HashMap<Character, Integer> dict = new HashMap<Character, Integer>();
        dict.put('I', 1);
        dict.put('V', 5);
        dict.put('X', 10);
        dict.put('L', 50);
        dict.put('C', 100);
        dict.put('D', 500);
        dict.put('M', 1000);
        int prevValue = 0;
        int result = 0;
        int curValue = 0;

        for(int i = 0; i < s.length(); i++) {
            curValue = dict.get(s.charAt(i));
            if (prevValue != 0 && prevValue < curValue) {
                result = result + curValue - 2 * prevValue;
            }else {
                result = result + curValue;
            }
            prevValue = curValue;
        }
        return result;
    }
}

还是要熟悉语言啊