168. Excel Sheet Column Title

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 

Credits:

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

class Solution {public:    string convertToTitle(int n) {        //return n == 0 ? "" : convertToTitle((n-1) / 26) + (string) (--n % 26 + 'A');//错解，由于运算顺序由右到左，所以n不能再次减一了。//char不能是string，会报错  return n == 0 ? "" : convertToTitle(n / 26) + (char) (--n % 26 + 'A');    }};