LeetCode——整数转罗马数字

题目地址：https://leetcode-cn.com/problems/integer-to-roman/

解题思路: 打一个模板然后分情况讨论。写的比较丑。

map<int, string> mp;
map<int, string> ::iterator it;
class Solution {
public:
    string resolve(int xnum,int x,int flag) {
        string s = "";
        if (xnum >= 0) {
            if (xnum == 4)
                s += mp[9 * flag];
            else {
                s += mp[5 * flag];
                while (xnum--)
                    s += mp[1 * flag];
            }
        }
        else
            if (x == 4)
                s+=mp[4*flag];
            else
                while (x--)
                    s+=mp[1*flag];
        return s;
    }
    string intToRoman(int num) {
        int index[13] = { 1,4,5,9,10,40,50,90,100,400,500,900,1000 };
        string tmp[13] = { "I","IV","V","IX","X","XL","L","XC","C","CD","D","CM","M" };
        string  sReturn = "";
        for (int i = 0; i < 13; i++)
            mp[index[i]] = tmp[i]; 
        if (mp.find(num) != mp.end())
            sReturn += mp[num];
        else {
            int g=num%10;//个位数
            int gnum = g - 5;//输出次数
            int s = num / 10 % 10;//十位数
            int snum = s - 5;//输出次数
            int b = num / 100 % 10;//百位数
            int bnum = b - 5;//输出次数
            int q= num / 1000 ;//千位数
            while (q--) 
                sReturn += mp[1000];
            sReturn+=resolve(bnum, b, 100);
            sReturn+=resolve(snum, s , 10);
            sReturn+=resolve(gnum, g, 1);
        }
        return sReturn;
    }
};