Leetcode: Excel Sheet Column Title

    1 -> A
    2 -> B
    3 -> C
    ...
    26 -> Z
    27 -> AA
    28 -> AB 

class Solution {
public:
    string convertToTitle(int n)
	{
		if (n < 1)
		{
			return "";
		} 
		else
		{
			string result = "";
			while (n)
			{
				n--;
				char ch = n % 26 + 'A';
				result += ch;
				n /= 26;
			}
			reverse(result.begin(), result.end());
			return result;
		}
	}
};