repeated-string-match

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Algorithms

Given two strings <code>a</code> and <code>b</code>, return the minimum number of times you should repeat string <code>a</code> so that string <code>b</code> is a substring of it. If it is impossible for <code>b</code>​​​​​​ to be a substring of <code>a</code> after repeating it, return <code>-1</code>.

Notice: string <code>&quot;abc&quot;</code> repeated 0 times is <code>&quot;&quot;</code>, repeated 1 time is <code>&quot;abc&quot;</code> and repeated 2 times is <code>&quot;abcabc&quot;</code>.

&nbsp;
Example 1:

<pre>
Input: a = &quot;abcd&quot;, b = &quot;cdabcdab&quot;
Output: 3
Explanation: We return 3 because by repeating a three times &quot;abcdabcdabcd&quot;, b is a substring of it.
</pre>

Example 2:

<pre>
Input: a = &quot;a&quot;, b = &quot;aa&quot;
Output: 2
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= a.length, b.length &lt;= 104</code></li>
	<li><code>a</code> and <code>b</code> consist of lowercase English letters.</li>
</ul>

repeatedStringMatch

Repeated String Match

Repeated Substring Pattern

repeated-substring-pattern

重复的子字符串

String

String Matching

给定两个字符串&nbsp;<code>a</code> 和 <code>b</code>，寻找重复叠加字符串 <code>a</code> 的最小次数，使得字符串 <code>b</code> 成为叠加后的字符串 <code>a</code> 的子串，如果不存在则返回 <code>-1</code>。

注意：字符串 <code>&quot;abc&quot;</code>&nbsp;重复叠加 0 次是 <code>&quot;&quot;</code>，重复叠加 1 次是&nbsp;<code>&quot;abc&quot;</code>，重复叠加 2 次是&nbsp;<code>&quot;abcabc&quot;</code>。

&nbsp;

示例 1：

<pre>输入：a = &quot;abcd&quot;, b = &quot;cdabcdab&quot;
输出：3
解释：a 重复叠加三遍后为 &quot;abcdabcdabcd&quot;, 此时 b 是其子串。
</pre>

示例 2：

<pre>输入：a = &quot;a&quot;, b = &quot;aa&quot;
输出：2
</pre>

示例 3：

<pre>输入：a = &quot;a&quot;, b = &quot;a&quot;
输出：1
</pre>

示例 4：

<pre>输入：a = &quot;abc&quot;, b = &quot;wxyz&quot;
输出：-1
</pre>

&nbsp;

提示：

<ul>
	<li><code>1 &lt;= a.length &lt;= 104</code></li>
	<li><code>1 &lt;= b.length &lt;= 104</code></li>
	<li><code>a</code> 和 <code>b</code> 由小写英文字母组成</li>
</ul>