<p>Given an integer <code>n</code>, return <em>a binary string representing its representation in base</em> <code>-2</code>.</p> <p><strong>Note</strong> that the returned string should not have leading zeros unless the string is <code>"0"</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> n = 2 <strong>Output:</strong> "110" <strong>Explantion:</strong> (-2)<sup>2</sup> + (-2)<sup>1</sup> = 2 </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> n = 3 <strong>Output:</strong> "111" <strong>Explantion:</strong> (-2)<sup>2</sup> + (-2)<sup>1</sup> + (-2)<sup>0</sup> = 3 </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> n = 4 <strong>Output:</strong> "100" <strong>Explantion:</strong> (-2)<sup>2</sup> = 4 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>0 <= n <= 10<sup>9</sup></code></li> </ul>