Excel Sheet Column Title

題目: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 

通過的程序如下:

public class Solution {
    public String convertToTitle(int n) {
         int index = 26;
        String excelTitle = "";
        int temp = n;
        while (temp > 0) {
            int mod = temp % index;
            temp = temp / index;
            if (mod == 0) {
                temp--;
                excelTitle = 'Z' + excelTitle;
            } else {
                excelTitle = (char)('A' -1 + mod) +excelTitle;
            }
        }
        return  excelTitle;
    }
}