Excel Sheet Column Title

Desicription

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

For example:

1
2
3
4
5
6
7
8
1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB 
...

Example 1:

1
2
Input: 1
Output: "A"

Example 2:

1
2
Input: 28
Output: "AB"

Example 3:

1
2
Input: 701
Output: "ZY"

Solution

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