1044\. Longest Duplicate Substring

Hard

Given a string `s`, consider all _duplicated substrings_: (contiguous) substrings of s that occur 2 or more times. The occurrences may overlap.

Return **any** duplicated substring that has the longest possible length. If `s` does not have a duplicated substring, the answer is `""`.

**Example 1:**

**Input:** s = "banana"

**Output:** "ana"

**Example 2:**

**Input:** s = "abcd"

**Output:** ""

**Constraints:**

*   <code>2 <= s.length <= 3 * 10<sup>4</sup></code>
*   `s` consists of lowercase English letters.