<p>Given a string <code>s</code>, consider all <em>duplicated substrings</em>: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap.</p> <p>Return <strong>any</strong> duplicated substring that has the longest possible length. If <code>s</code> does not have a duplicated substring, the answer is <code>""</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre><strong>Input:</strong> s = "banana" <strong>Output:</strong> "ana" </pre><p><strong class="example">Example 2:</strong></p> <pre><strong>Input:</strong> s = "abcd" <strong>Output:</strong> "" </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>2 <= s.length <= 3 * 10<sup>4</sup></code></li> <li><code>s</code> consists of lowercase English letters.</li> </ul>