Project Notes

Regular Expression Matching

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Description

tab: English
 
<p>Given an input string <code>s</code>&nbsp;and a pattern <code>p</code>, implement regular expression matching with support for <code>&#39;.&#39;</code> and <code>&#39;*&#39;</code> where:</p>
 
<ul>
	<li><code>&#39;.&#39;</code> Matches any single character.​​​​</li>
	<li><code>&#39;*&#39;</code> Matches zero or more of the preceding element.</li>
</ul>
 
<p>The matching should cover the <strong>entire</strong> input string (not partial).</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;aa&quot;, p = &quot;a&quot;
<strong>Output:</strong> false
<strong>Explanation:</strong> &quot;a&quot; does not match the entire string &quot;aa&quot;.
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;aa&quot;, p = &quot;a*&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> &#39;*&#39; means zero or more of the preceding element, &#39;a&#39;. Therefore, by repeating &#39;a&#39; once, it becomes &quot;aa&quot;.
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;ab&quot;, p = &quot;.*&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> &quot;.*&quot; means &quot;zero or more (*) of any character (.)&quot;.
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length&nbsp;&lt;= 20</code></li>
	<li><code>1 &lt;= p.length&nbsp;&lt;= 20</code></li>
	<li><code>s</code> contains only lowercase English letters.</li>
	<li><code>p</code> contains only lowercase English letters, <code>&#39;.&#39;</code>, and&nbsp;<code>&#39;*&#39;</code>.</li>
	<li>It is guaranteed for each appearance of the character <code>&#39;*&#39;</code>, there will be a previous valid character to match.</li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/regular-expression-matching/submissions/) | [solutions](https://leetcode.com/problems/regular-expression-matching/solutions/)
 
 
tab: 中文
 
<p>给你一个字符串&nbsp;<code>s</code>&nbsp;和一个字符规律&nbsp;<code>p</code>，请你来实现一个支持 <code>'.'</code>&nbsp;和&nbsp;<code>'*'</code>&nbsp;的正则表达式匹配。</p>
 
<ul>
	<li><code>'.'</code> 匹配任意单个字符</li>
	<li><code>'*'</code> 匹配零个或多个前面的那一个元素</li>
</ul>
 
<p>所谓匹配，是要涵盖&nbsp;<strong>整个&nbsp;</strong>字符串&nbsp;<code>s</code> 的，而不是部分字符串。</p>
&nbsp;
 
<p><strong>示例 1：</strong></p>
 
<pre>
<strong>输入：</strong>s = "aa", p = "a"
<strong>输出：</strong>false
<strong>解释：</strong>"a" 无法匹配 "aa" 整个字符串。
</pre>
 
<p><strong>示例 2:</strong></p>
 
<pre>
<strong>输入：</strong>s = "aa", p = "a*"
<strong>输出：</strong>true
<strong>解释：</strong>因为 '*' 代表可以匹配零个或多个前面的那一个元素, 在这里前面的元素就是 'a'。因此，字符串 "aa" 可被视为 'a' 重复了一次。
</pre>
 
<p><strong>示例&nbsp;3：</strong></p>
 
<pre>
<strong>输入：</strong>s = "ab", p = ".*"
<strong>输出：</strong>true
<strong>解释：</strong>".*" 表示可匹配零个或多个（'*'）任意字符（'.'）。
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length&nbsp;&lt;= 20</code></li>
	<li><code>1 &lt;= p.length&nbsp;&lt;= 20</code></li>
	<li><code>s</code>&nbsp;只包含从&nbsp;<code>a-z</code>&nbsp;的小写字母。</li>
	<li><code>p</code>&nbsp;只包含从&nbsp;<code>a-z</code>&nbsp;的小写字母，以及字符&nbsp;<code>.</code>&nbsp;和&nbsp;<code>*</code>。</li>
	<li>保证每次出现字符&nbsp;<code>*</code> 时，前面都匹配到有效的字符</li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/regular-expression-matching/submissions/) | [题解](https://leetcode.cn/problems/regular-expression-matching/solution/)

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