# leetcode\_168

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 
...
```

Example 1:

Input: 1 Output: "A" Example 2:

Input: 28 Output: "AB" Example 3:

Input: 701 Output: "ZY"

## Solutions

1. **math**
2. Check description in leetcode.

```cpp
class Solution {
public:
    string convertToTitle(int n) {
        string res;
        while (n > 0) {
            // key point
            n--;
            res += 'A' + (n % 26);
            n /= 26;
        }
        reverse(res.begin(), res.end());
        return res;
    }
};
```