leetcode No.168 Excel表列名称

//一行代码
class Solution {
    public String convertToTitle(int n) {
        return n==0? "":convertToTitle(--n/26)+(char)('A'+(n%26));
    }
}

//常规代码
public String convertToTitle(int n) {
        if (n <= 0) {
            return "";
        }
        StringBuilder sb = new StringBuilder();
        while (n > 0) {
            n--;
            sb.append((char) (n % 26 + 'A'));
            n =n / 26;
        }
        return sb.reverse().toString();
    }