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47 lines
2.5 KiB
HTML
47 lines
2.5 KiB
HTML
<p>Given an array of characters <code>chars</code>, compress it using the following algorithm:</p>
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<p>Begin with an empty string <code>s</code>. For each group of <strong>consecutive repeating characters</strong> in <code>chars</code>:</p>
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<ul>
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<li>If the group's length is <code>1</code>, append the character to <code>s</code>.</li>
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<li>Otherwise, append the character followed by the group's length.</li>
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</ul>
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<p>The compressed string <code>s</code> <strong>should not be returned separately</strong>, but instead, be stored <strong>in the input character array <code>chars</code></strong>. Note that group lengths that are <code>10</code> or longer will be split into multiple characters in <code>chars</code>.</p>
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<p>After you are done <strong>modifying the input array,</strong> return <em>the new length of the array</em>.</p>
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<p>You must write an algorithm that uses only constant extra space.</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> chars = ["a","a","b","b","c","c","c"]
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<strong>Output:</strong> Return 6, and the first 6 characters of the input array should be: ["a","2","b","2","c","3"]
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<strong>Explanation:</strong> The groups are "aa", "bb", and "ccc". This compresses to "a2b2c3".
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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> chars = ["a"]
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<strong>Output:</strong> Return 1, and the first character of the input array should be: ["a"]
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<strong>Explanation:</strong> The only group is "a", which remains uncompressed since it's a single character.
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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> chars = ["a","b","b","b","b","b","b","b","b","b","b","b","b"]
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<strong>Output:</strong> Return 4, and the first 4 characters of the input array should be: ["a","b","1","2"].
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<strong>Explanation:</strong> The groups are "a" and "bbbbbbbbbbbb". This compresses to "ab12".</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 <= chars.length <= 2000</code></li>
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<li><code>chars[i]</code> is a lowercase English letter, uppercase English letter, digit, or symbol.</li>
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</ul>
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