> For the complete documentation index, see [llms.txt](https://junnie.gitbook.io/nine-chapter/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://junnie.gitbook.io/nine-chapter/1.binary-search/1044.-longest-duplicate-substring-h.md).

# 1044. Longest Duplicate Substring (H)

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:**

* `2 <= s.length <= 3 * 104`
* `s` consists of lowercase English letters.

### **Solution:**

<https://raghu-keerthisree.gitbook.io/june-leetcoding-challenge/week-3/longest-duplicate-substring><br>