<p>Given an integer <code>n</code>, return <code>true</code> <em>if it is possible to represent </em><code>n</code><em> as the sum of distinct powers of three.</em> Otherwise, return <code>false</code>.</p> <p>An integer <code>y</code> is a power of three if there exists an integer <code>x</code> such that <code>y == 3<sup>x</sup></code>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> n = 12 <strong>Output:</strong> true <strong>Explanation:</strong> 12 = 3<sup>1</sup> + 3<sup>2</sup> </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> n = 91 <strong>Output:</strong> true <strong>Explanation:</strong> 91 = 3<sup>0</sup> + 3<sup>2</sup> + 3<sup>4</sup> </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> n = 21 <strong>Output:</strong> false </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 10<sup>7</sup></code></li> </ul>