实在不知道这道题有啥难的，只是我没写的很标准而已

class Solution {
public:
string intToRoman(int num) {string strret="";auto divid = num/1000;for(int i=0; i<divid; ++i)strret += 'M';num %= 1000;divid = num/100;if(divid==9)strret += "CM";else if(4==divid)strret += "CD";else if(divid <4)for(int i=0; i<divid; ++i)strret += 'C';else if(divid >4){strret += 'D';for(int i=0; i<divid-5; ++i)strret += 'C';}num %= 100;divid = num/10;if(divid==9)strret += "XC";else if(4==divid)strret += "XL";else if(divid <4)for(int i=0; i<divid; ++i)strret += 'X';else{strret += 'L';for(int i=0; i<divid-5; ++i)strret += 'X';}num %= 10;divid = num;if(divid == 9)strret += "IX";else if(4==divid)strret += "IV";else if(divid<4)for(int i=0; i<divid; ++i)strret += 'I';else {strret += 'V';for(int i=0; i<divid-5; ++i)strret += 'I';}return strret;
}};