description:

把阿拉伯数字转换成罗马数字

Note:

Example 1:

Input: 3
Output: "III"
Example 2:

Input: 4
Output: "IV"
Example 3:

Input: 9
Output: "IX"
Example 4:

Input: 58
Output: "LVIII"
Explanation: L = 50, V = 5, III = 3.
Example 5:

Input: 1994
Output: "MCMXCIV"
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.

my answer:

感恩

大佬的answer：真的在leetcode里写代码的时候要时刻注意还是不是英文半角，要不然真的崩溃，哪出错都不知道

class Solution {
public:
    string intToRoman(int num) {
        string res = "";
        vector<int> value = {1000, 500, 100, 50, 10, 5, 1};
        vector<char> roman = {'M', 'D', 'C', 'L', 'X', 'V', 'I'};
        for(int n = 0; n < 7; n += 2){
            int x = num / value[n];
            if (x < 4){
                for (int i = 1; i <= x; i++) res += roman[n];
            }
            else if(x == 4){
                res = res + roman[n] + roman[n - 1];
            }
            else if(x > 4 && x < 9){
                res += roman[n - 1];
                for (int i = 6; i <= x; i++) res += roman[n];
            
            }else if(x == 9){
                res = res + roman[n] + roman[n -2];
            } 
            num %= value[n];
        }
        return res;
    }
};

relative point get√：

hint :

在4和9处讨论好分割点，其实比较easy辣，思路逻辑神马的都还ok。