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38 lines
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38 lines
1.4 KiB
HTML
<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>
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<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>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> s = "A man, a plan, a canal: Panama"
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<strong>Output:</strong> true
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<strong>Explanation:</strong> "amanaplanacanalpanama" is a palindrome.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> s = "race a car"
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<strong>Output:</strong> false
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<strong>Explanation:</strong> "raceacar" is not a palindrome.
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</pre>
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<p><strong class="example">Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> s = " "
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<strong>Output:</strong> true
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<strong>Explanation:</strong> s is an empty string "" after removing non-alphanumeric characters.
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Since an empty string reads the same forward and backward, it is a palindrome.
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>1 <= s.length <= 2 * 10<sup>5</sup></code></li>
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<li><code>s</code> consists only of printable ASCII characters.</li>
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</ul>
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