【Leetcode】Roman to Integer

问题描述

Given a roman numeral, convert it to an integer.

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

罗马数字转数字，如VII=7

只要了解规则即可

代码

class Solution {
private:
	map<char, int> m;
		
public:
	Solution(){
		m['I'] = 1;  
        m['V'] = 5;  
        m['X'] = 10;  
        m['L'] = 50;  
        m['C'] = 100;  
        m['D'] = 500;  
        m['M'] = 1000;
	}
    int romanToInt(string s) {
		int r = m[s[0]];
		for(int i=1;i<s.size();i++){
			int tmp = m[s[i]];
			if(tmp <= m[s[i-1]]){
				r += tmp;
			} else {
				r -= m[s[i-1]];
				r += tmp - m[s[i-1]];
			}
		}
		return r;
    }
};