leetcode-java-168. Excel Sheet Column Title

思路：
其实就是十进制转换成26进制

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