> For the complete documentation index, see [llms.txt](https://jaywin.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jaywin.gitbook.io/leetcode/solutions/0459-repeated-substring-pattern.md).

# 0459. Repeated Substring Pattern

<https://leetcode.com/problems/repeated-substring-pattern>

## Description

Given a string `s`, check if it can be constructed by taking a substring of it and appending multiple copies of the substring together.

**Example 1:**

```
**Input:** s = "abab"
**Output:** true
**Explanation:** It is the substring "ab" twice.
```

**Example 2:**

```
**Input:** s = "aba"
**Output:** false
```

**Example 3:**

```
**Input:** s = "abcabcabcabc"
**Output:** true
**Explanation:** It is the substring "abc" four times or the substring "abcabc" twice.
```

**Constraints:**

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

## ac

```java
```