Leetcode 13 Roman to Integer

Leetcode 13 Roman to Integer

//罗马数字采用七个罗马字母作数字//即Ⅰ（1）、X（10）、C（100）、M（1000）、V（5）、L（50）、D（500）#include <string>using namespace std;class Solution {public:    int romanNumber(char c){        switch (c){        case'I':            return 1;        case'X':            return 10;        case'C':            return 100;        case'M':            return 1000;        case'V':            return 5;        case'L':            return 50;        case'D':            return 500;        }       }    int romanToInt(string s) {        int sum = 0;        int max = 1;        for (int i = s.size() - 1; i >=0 ; i--){            if (romanNumber(s[i]) >= max){                max = romanNumber(s[i]);                sum += max;            }            else{                sum -= romanNumber(s[i]);            }        }        return sum;    }};/*用map比较明智啊class Solution {public:    int romanToInt(string s) {        vector<pair<char, int>> map;        map.push_back({'I',1});        map.push_back({'V',5});        map.push_back({'X',10});        map.push_back({'L',50});        map.push_back({'C',100});        map.push_back({'D',500});        map.push_back({'M',1000});        int j, last=-1, ret = 0;        for(int i=s.size()-1;i>=0;i--)        {            for(j=0;j<map.size();j++)            {                if(map[j].first==s[i])                {                    if(j<last)                    {                        ret = ret-map[j].second;                        last = -1;                    }                    else                    {                        ret = ret+map[j].second;                        last = j;                    }                }            }        }        return ret;    }    };*/