Encode Number
<p>Given a non-negative integer <code>num</code>, Return its <em>encoding</em> string.</p>

<p>The encoding is done by converting the integer to a string using a secret function that you should deduce from the following table:</p>

<p><img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/1200-1299/1256.Encode%20Number/images/encode_number.png" style="width: 164px; height: 360px;" /></p>

<p>&nbsp;</p>

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

<pre>

<strong>Input:</strong> num = 23

<strong>Output:</strong> &quot;1000&quot;

</pre>

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

<pre>

<strong>Input:</strong> num = 107

<strong>Output:</strong> &quot;101100&quot;

</pre>

<p>&nbsp;</p>

<p><strong>Constraints:</strong></p>

<ul>

    <li><code>0 &lt;= num &lt;= 10^9</code></li>

</ul>
Bit Manipulation; Math; String
class Solution {
public:
    string encode(int num) {
        bitset<32> bs(++num);
        string ans = bs.to_string();
        int i = 0;
        while (ans[i] == '0') {
            ++i;
        }
        return ans.substr(i + 1);
    }
};