168

168. Excel Sheet Column Title (Easy)

Given an integer columnNumber, return its corresponding column title as it appears in an Excel sheet.

For example:

A -> 1
B -> 2
C -> 3
...
Z -> 26
AA -> 27
AB -> 28 
...

 

Example 1:

Input: columnNumber = 1
Output: "A"

Example 2:

Input: columnNumber = 28
Output: "AB"

Example 3:

Input: columnNumber = 701
Output: "ZY"

 

Constraints:

• 1 <= columnNumber <= 231 - 1

Companies: Microsoft, Apple, Amazon

Related Topics:
Math, String

Similar Questions:

• Excel Sheet Column Number (Easy)
• Cells in a Range on an Excel Sheet (Easy)

Solution 1.

// OJ: https://leetcode.com/problems/excel-sheet-column-title
// Author: github.com/lzl124631x
// Time: O(log_26^N)
// Space: O(1) extra space
class Solution {
public:
    string convertToTitle(int n) {
        string ans;
        while (n) {
            n--;
            ans += 'A' + n % 26;
            n /= 26;
        }
        reverse(begin(ans), end(ans));
        return ans;
    }
};