【LeetCode】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 

Solution： 由于A->1,  计算s的末尾时需先减去1

 1 class Solution {
 2 public:
 3     string convertToTitle(int n) {
 4         string s;
 5         while(n){
 6             s =  (char)(‘A‘+(n-1)%26)+s;
 7             n = (n-1)/26;
 8         }
 9         return s;
10     }
11 };