Given a positive integer, return its corresponding column title as appear in an Excel sheet.
For example:
1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB
class Solution {//怪恶心的一道题
public:
string convertToTitle(int n) {
string s;
while(n!=0){
n-=1;
s.insert(s.begin(),1,'A'+n%26);
n/=26;
}
return s;
}
};