Question

link

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 

Credits:
Special thanks to @ifanchu for adding this problem and creating all test cases.

            <div id="tags" class="btn btn-xs btn-warning">Show Tags</div>
            <span class="hide">
              
              <a class="btn btn-xs btn-primary" href="/tag/math/">Math</a>
              
            </span>
          
        </div>

Analysis

This is pretty much a similar question. It’s pretty easy.

Code

public class Solution {
    public int titleToNumber(String s) {
        if (s == null || s.length() == 0) {
            return 0;
        }
        int sum = 0;
        for (char ch: s.toCharArray()) {
            sum *= 26;
            sum += (int) (ch - 'A' + 1);
        }
        return sum;
    }
}