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52 lines
2.1 KiB
HTML
52 lines
2.1 KiB
HTML
<p>You are given a string <code>s</code> and an integer <code>k</code>.</p>
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<p>Determine if there exists a <span data-keyword="substring-nonempty">substring</span> of length <strong>exactly</strong> <code>k</code> in <code>s</code> that satisfies the following conditions:</p>
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<ol>
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<li>The substring consists of <strong>only one distinct character</strong> (e.g., <code>"aaa"</code> or <code>"bbb"</code>).</li>
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<li>If there is a character <strong>immediately before</strong> the substring, it must be different from the character in the substring.</li>
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<li>If there is a character <strong>immediately after</strong> the substring, it must also be different from the character in the substring.</li>
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</ol>
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<p>Return <code>true</code> if such a substring exists. Otherwise, return <code>false</code>.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">s = "aaabaaa", k = 3</span></p>
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<p><strong>Output:</strong> <span class="example-io">true</span></p>
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<p><strong>Explanation:</strong></p>
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<p>The substring <code>s[4..6] == "aaa"</code> satisfies the conditions.</p>
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<ul>
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<li>It has a length of 3.</li>
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<li>All characters are the same.</li>
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<li>The character before <code>"aaa"</code> is <code>'b'</code>, which is different from <code>'a'</code>.</li>
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<li>There is no character after <code>"aaa"</code>.</li>
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</ul>
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</div>
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<p><strong class="example">Example 2:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">s = "abc", k = 2</span></p>
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<p><strong>Output:</strong> <span class="example-io">false</span></p>
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<p><strong>Explanation:</strong></p>
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<p>There is no substring of length 2 that consists of one distinct character and satisfies the conditions.</p>
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</div>
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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 <= k <= s.length <= 100</code></li>
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<li><code>s</code> consists of lowercase English letters only.</li>
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</ul>
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