168.Excel Sheet Column Title(28 -> AB)

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 

代码：

public class Solution {
    public String convertToTitle(int n) {
        String res = "";
    while(n!=0){
        res=(char)((n-1)%26+'A')+res;
        n = (n-1)/26 ; 
        }
    return res;
    }
}