Roman to Integer & Integer to Roman

题目：

Given a roman numeral, convert it to an integer.

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

解析：

这题没兴趣做，抄答案

http://blog.csdn.net/jellyyin/article/details/13165731

class Solution {
public:
    int romanToInt(string s) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        int result=0;
        
        map<char,int> roman;
        roman['I']=1;
        roman['V']=5;
        roman['X']=10;
        roman['L']=50;
        roman['C']=100;
        roman['D']=500;
        roman['M']=1000;
        
        for(int i=s.length()-1;i>=0;i--)
        {
            if(i==s.length()-1)
            {
                result=roman[s[i]];
                continue;
            }
            if(roman[s[i]] >= roman[s[i+1]])
                result+=roman[s[i]];
            else
                result-=roman[s[i]];
        }
        return result;
    }
};

题目：

Given an integer, convert it to a roman numeral.

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

解析：

class Solution {
public:
    string intToRoman(int num) {
        const int radix[] = {1000, 900, 500, 400, 100, 90,
            50, 40, 10, 9, 5, 4, 1};
        const string symbol[] = {"M", "CM", "D", "CD", "C", "XC",
            "L", "XL", "X", "IX", "V", "IV", "I"};
        string roman;
        for (size_t i = 0; num > 0; ++i) {
            int count = num / radix[i];
            num %= radix[i];
            for (; count > 0; --count) roman += symbol[i];
        }
        return roman;
    }
};