30 lines
912 B
Markdown
30 lines
912 B
Markdown
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A phrase is a **palindrome** 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.
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Given a string `s`, return `true` _if it is a **palindrome**, or_ `false` _otherwise_.
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**Example 1:**
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Input: s = "A man, a plan, a canal: Panama"
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Output: true
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Explanation: "amanaplanacanalpanama" is a palindrome.
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**Example 2:**
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Input: s = "race a car"
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Output: false
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Explanation: "raceacar" is not a palindrome.
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**Example 3:**
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Input: s = " "
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Output: true
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Explanation: 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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**Constraints:**
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* `1 <= s.length <= 2 * 105`
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* `s` consists only of printable ASCII characters.
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