[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

Thought process:
Think of the result as a number format where each digit can have 26 numbers.

Solution:

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class Solution {
    public String convertToTitle(int n) {
        StringBuilder sb = new StringBuilder();
        
        while (n >  0) {
            n--;
            sb.append((char)('A' + n % 26));
            n /= 26;
        }
        return sb.reverse().toString();
    }
}

Time complexity: O(n / 26) = O(n).
Location: Philadelphia, PA, USA

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