leetcode Excel Sheet Column Title

原题链接：https://leetcode.com/problems/excel-sheet-column-title/

Description

Given a positive integer, return its corresponding column title as appear in an Excel sheet.

For example:

1 -> A2 -> B3 -> C...26 -> Z27 -> AA28 -> AB 

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