LeetCode 0168 - Excel Sheet Column Title

1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB 
...

Input: 1
Output: "A"

Input: 28
Output: "AB"

Input: 701
Output: "ZY"

class Solution {
public:
    string convertToTitle(int n) {
        string res;
        while(n) {
            res = string(1, (n - 1) % 26 + 'A') + res;
            n = (n - 1) / 26;
        }
        return res;
    }
};