<p>Given an integer <code>columnNumber</code>, return <em>its corresponding column title as it appears in an Excel sheet</em>.</p>

<p>For example:</p>

<pre>
A -&gt; 1
B -&gt; 2
C -&gt; 3
...
Z -&gt; 26
AA -&gt; 27
AB -&gt; 28 
...
</pre>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> columnNumber = 1
<strong>Output:</strong> &quot;A&quot;
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> columnNumber = 28
<strong>Output:</strong> &quot;AB&quot;
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> columnNumber = 701
<strong>Output:</strong> &quot;ZY&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= columnNumber &lt;= 2<sup>31</sup> - 1</code></li>
</ul>

class Solution {
public:
    string convertToTitle(int columnNumber) {
        string s;
        while(columnNumber>0){
            if(columnNumber % 26 ==0){
                int digit = 'Z';
                s.push_back(digit);
                columnNumber = columnNumber/26 -1;
            }else{
                int digit = (columnNumber%26)+'A' - 1;
                s.push_back(digit);
                columnNumber = columnNumber / 26;
            }
            
        }
        reverse(s.begin(),s.end());
        return s;
    }
};
7400