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74 lines
3.3 KiB
HTML
74 lines
3.3 KiB
HTML
<p>You are given an integer <code>n</code> and an <strong>undirected</strong> graph with <code>n</code> nodes labeled from 0 to <code>n - 1</code> and a 2D array <code>edges</code>, where <code>edges[i] = [u<sub>i</sub>, v<sub>i</sub>]</code> indicates an edge between nodes <code>u<sub>i</sub></code> and <code>v<sub>i</sub></code>.</p>
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<p>You are also given a string <code>label</code> of length <code>n</code>, where <code>label[i]</code> is the character associated with node <code>i</code>.</p>
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<p>You may start at any node and move to any adjacent node, visiting each node <strong>at most</strong> once.</p>
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<p>Return the <strong>maximum</strong> possible length of a <strong><span data-keyword="palindrome-string">palindrome</span></strong> that can be formed by visiting a set of <strong>unique</strong> nodes along a valid path.</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">n = 3, edges = [[0,1],[1,2]], label = "aba"</span></p>
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<p><strong>Output:</strong> <span class="example-io">3</span></p>
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<p><strong>Exp</strong><strong>lanation:</strong></p>
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<p><img src="https://assets.leetcode.com/uploads/2025/06/13/screenshot-2025-06-13-at-230714.png" style="width: 250px; height: 85px;" /></p>
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<ul>
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<li>The longest palindromic path is from node 0 to node 2 via node 1, following the path <code>0 → 1 → 2</code> forming string <code>"aba"</code>.</li>
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<li>This is a valid palindrome of length 3.</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">n = 3, edges = [[0,1],[0,2]], label = "abc"</span></p>
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<p><strong>Output:</strong> <span class="example-io">1</span></p>
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<p><strong>Explanation:</strong></p>
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<p><img src="https://assets.leetcode.com/uploads/2025/06/13/screenshot-2025-06-13-at-230017.png" style="width: 200px; height: 150px;" /></p>
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<ul>
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<li>No path with more than one node forms a palindrome.</li>
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<li>The best option is any single node, giving a palindrome of length 1.</li>
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</ul>
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</div>
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<p><strong class="example">Example 3:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">n = 4, edges = [[0,2],[0,3],[3,1]], label = "bbac"</span></p>
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<p><strong>Output:</strong> <span class="example-io">3</span></p>
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<p><strong>Explanation:</strong></p>
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<p><img src="https://assets.leetcode.com/uploads/2025/06/13/screenshot-2025-06-13-at-230508.png" style="width: 200px; height: 200px;" /></p>
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<ul>
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<li>The longest palindromic path is from node 0 to node 1, following the path <code>0 → 3 → 1</code>, forming string <code>"bcb"</code>.</li>
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<li>This is a valid palindrome of length 3.</li>
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</ul>
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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 <= 14</code></li>
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<li><code>n - 1 <= edges.length <= n * (n - 1) / 2</code></li>
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<li><code>edges[i] == [u<sub>i</sub>, v<sub>i</sub>]</code></li>
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<li><code>0 <= u<sub>i</sub>, v<sub>i</sub> <= n - 1</code></li>
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<li><code>u<sub>i</sub> != v<sub>i</sub></code></li>
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<li><code>label.length == n</code></li>
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<li><code>label</code> consists of lowercase English letters.</li>
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<li>There are no duplicate edges.</li>
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</ul>
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