LeetCode 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 

public class Solution {
    public String convertToTitle(int n) {
        String ret="";
        
        while (n>0) {
            n--;
            char letter=(char) (n%26+'A');
            ret=letter+ret;
            n=n/26;
        }
        
        return ret;
        
    }
}