LeetCode 168. Excel Sheet Column Title（Excel表列名称）（Java）

题目：

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 
...

Example 1:
Input: 1
Output: “A”

Example 2:
Input: 28
Output: “AB”

Example 3:
Input: 701
Output: “ZY”

解答：

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

class Solution {
    public String convertToTitle(int n) {
        if(n<=0){
            return null;
        }
        StringBuilder result = new StringBuilder();

        while(n>0){
            n--;
            result.insert(0,(char)('A'+n%26));
            n = n/26;
        }

        return result.toString();
    }
}

题目比较简单，但程序二似乎比程序一快一点？？