[算法練習]Excel Sheet Column Title

題目：

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

   

代碼：

class Solution {

public:

string convertToTitle(int n)

{

        const char ALPHA[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        int base = 26;

 

        string result;

        while (n)

        {

                int v = (n-1) % base;

                result += ALPHA[v];

 

                n = (n-1) / base;

        }

 

        reverse(result.begin(),result.end());

        return result;

}

};