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”
func convertToTitle(n int) string {
res := ""
for n > 0 {
n--
res = string(n%26+'A') + res
n = n / 26
}
return res
}
