[LeetCode]168. Excel Sheet Column Title

题目描述：

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 

思路：

Excel序是这样的：A~Z, AA~ZZ, AAA~ZZZ, ……
十进制数转26进制数
注意是从1开始的
将int值强制转化为char类型

public class Solution168 {
    public String convertToTitle(int n) {
        String res = "";
        while(n>0){
            res = (char)((n-1)%26+'A')+res;
            n=(n-1)/26;
        }
        return res;
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Solution168 solution168 = new Solution168();
        int n = 27;
        System.out.println(solution168.convertToTitle(n));
    }

}