思路可以看这个链接:https://biaodigit.github.io/LeetCode/0012/#%E8%A7%A3%E9%A2%98%E6%80%9D%E8%B7%AF-%E8%B4%AA%E5%BF%83%E7%AE%97%E6%B3%95
#include<bits/stdc++.h>
using namespace std;
int arr[20]={1000,900,500,400,100,90,50,40,10,9,5,4,1};//13
string sl[20]={"M","CM","D","CD","C","XC","L","XL...