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72 lines
4.0 KiB
HTML
72 lines
4.0 KiB
HTML
<p>You are given a string array <code>words</code> and a <strong>binary</strong> array <code>groups</code> both of length <code>n</code>, where <code>words[i]</code> is associated with <code>groups[i]</code>.</p>
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<p>Your task is to select the <strong>longest alternating</strong> <span data-keyword="subsequence-array">subsequence</span> from <code>words</code>. A subsequence of <code>words</code> is alternating if for any two consecutive strings in the sequence, their corresponding elements in the binary array <code>groups</code> differ. Essentially, you are to choose strings such that adjacent elements have non-matching corresponding bits in the <code>groups</code> array.</p>
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<p>Formally, you need to find the longest subsequence of an array of indices <code>[0, 1, ..., n - 1]</code> denoted as <code>[i<sub>0</sub>, i<sub>1</sub>, ..., i<sub>k-1</sub>]</code>, such that <code>groups[i<sub>j</sub>] != groups[i<sub>j+1</sub>]</code> for each <code>0 <= j < k - 1</code> and then find the words corresponding to these indices.</p>
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<p>Return <em>the selected subsequence. If there are multiple answers, return <strong>any</strong> of them.</em></p>
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<p><strong>Note:</strong> The elements in <code>words</code> are distinct.</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" style="
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border-color: var(--border-tertiary);
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border-left-width: 2px;
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color: var(--text-secondary);
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font-size: .875rem;
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margin-bottom: 1rem;
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margin-top: 1rem;
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overflow: visible;
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padding-left: 1rem;
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">
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<p><strong>Input:</strong> <span class="example-io" style="
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font-family: Menlo,sans-serif;
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font-size: 0.85rem;
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">words = ["e","a","b"], groups = [0,0,1]</span></p>
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<p><strong>Output:</strong> <span class="example-io" style="
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font-family: Menlo,sans-serif;
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font-size: 0.85rem;
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">["e","b"]</span></p>
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<p><strong>Explanation:</strong> A subsequence that can be selected is <code>["e","b"]</code> because <code>groups[0] != groups[2]</code>. Another subsequence that can be selected is <code>["a","b"]</code> because <code>groups[1] != groups[2]</code>. It can be demonstrated that the length of the longest subsequence of indices that satisfies the condition is <code>2</code>.</p>
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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" style="
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border-color: var(--border-tertiary);
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border-left-width: 2px;
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color: var(--text-secondary);
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font-size: .875rem;
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margin-bottom: 1rem;
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margin-top: 1rem;
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overflow: visible;
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padding-left: 1rem;
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">
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<p><strong>Input:</strong> <span class="example-io" style="
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font-family: Menlo,sans-serif;
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font-size: 0.85rem;
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">words = ["a","b","c","d"], groups = [1,0,1,1]</span></p>
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<p><strong>Output:</strong> <span class="example-io" style="
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font-family: Menlo,sans-serif;
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font-size: 0.85rem;
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">["a","b","c"]</span></p>
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<p><strong>Explanation:</strong> A subsequence that can be selected is <code>["a","b","c"]</code> because <code>groups[0] != groups[1]</code> and <code>groups[1] != groups[2]</code>. Another subsequence that can be selected is <code>["a","b","d"]</code> because <code>groups[0] != groups[1]</code> and <code>groups[1] != groups[3]</code>. It can be shown that the length of the longest subsequence of indices that satisfies the condition is <code>3</code>.</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 <= n == words.length == groups.length <= 100</code></li>
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<li><code>1 <= words[i].length <= 10</code></li>
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<li><code>groups[i]</code> is either <code>0</code> or <code>1.</code></li>
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<li><code>words</code> consists of <strong>distinct</strong> strings.</li>
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<li><code>words[i]</code> consists of lowercase English letters.</li>
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</ul>
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