leetcode 168. Excel Sheet Column Title

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 {
public:
    string convertToTitle(int n) {
        string result = "";
        int flag = 0;
        n = n - 1;
        while(n >= 0) {
            result += 'A' + n % 26;
            n /= 26;
            n -= 1;
        }

        reverse(result.begin(), result.end());
        return result; 
    }
};