Project Notes

Valid Palindrome

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Description

tab: English
 
<p>A phrase is a <strong>palindrome</strong> if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.</p>
 
<p>Given a string <code>s</code>, return <code>true</code><em> if it is a <strong>palindrome</strong>, or </em><code>false</code><em> otherwise</em>.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;A man, a plan, a canal: Panama&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> &quot;amanaplanacanalpanama&quot; is a palindrome.
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot;race a car&quot;
<strong>Output:</strong> false
<strong>Explanation:</strong> &quot;raceacar&quot; is not a palindrome.
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> s = &quot; &quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> s is an empty string &quot;&quot; after removing non-alphanumeric characters.
Since an empty string reads the same forward and backward, it is a palindrome.
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length &lt;= 2 * 10<sup>5</sup></code></li>
	<li><code>s</code> consists only of printable ASCII characters.</li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/valid-palindrome/submissions/) | [solutions](https://leetcode.com/problems/valid-palindrome/solutions/)
 
 
tab: 中文
 
<p>如果在将所有大写字符转换为小写字符、并移除所有非字母数字字符之后，短语正着读和反着读都一样。则可以认为该短语是一个 <strong>回文串</strong> 。</p>
 
<p>字母和数字都属于字母数字字符。</p>
 
<p>给你一个字符串 <code>s</code>，如果它是 <strong>回文串</strong> ，返回 <code>true</code><em> </em>；否则，返回<em> </em><code>false</code><em> </em>。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1：</strong></p>
 
<pre>
<strong>输入:</strong> s = "A man, a plan, a canal: Panama"
<strong>输出：</strong>true
<strong>解释：</strong>"amanaplanacanalpanama" 是回文串。
</pre>
 
<p><strong>示例 2：</strong></p>
 
<pre>
<strong>输入：</strong>s = "race a car"
<strong>输出：</strong>false
<strong>解释：</strong>"raceacar" 不是回文串。
</pre>
 
<p><strong>示例 3：</strong></p>
 
<pre>
<strong>输入：</strong>s = " "
<strong>输出：</strong>true
<strong>解释：</strong>在移除非字母数字字符之后，s 是一个空字符串 "" 。
由于空字符串正着反着读都一样，所以是回文串。
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li><code>1 &lt;= s.length &lt;= 2 * 10<sup>5</sup></code></li>
	<li><code>s</code> 仅由可打印的 ASCII 字符组成</li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/valid-palindrome/submissions/) | [题解](https://leetcode.cn/problems/valid-palindrome/solution/)

Solutions & Notes

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