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 

一刷
题解：只能从后往前append,因为每次需要n--然后与26求余数。

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