【LeetCode】168. Excel Sheet Column Title

Excel Sheet Column Title

Given a non-zero 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 

Credits:
Special thanks to @ifanchu for adding this problem and creating all test cases.

Excel序是这样的：A~Z, AA~ZZ, AAA~ZZZ, ……

本质上就是将一个10进制数转换为一个26进制的数

注意：由于下标从1开始而不是从0开始，因此要减一操作。

class Solution {
public:
    string convertToTitle(int n) {
        string ret = "";
        while(n)
        {
            ret = (char)((n-1)%26+'A') + ret;
            n = (n-1)/26;
        }
        return ret;
    }
};