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

给定一个数，转换成Excel的字母表示形式，实际上就是一个十进制数字转26进制运算。代码如下：

public class Solution {
    public String convertToTitle(int n) {
        StringBuilder sb = new StringBuilder();
        for(; n > 0; n /= 26) {
            sb.insert(0, (char)('A' + --n % 26));
        }
        return sb.toString();
    }
}