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77 lines
3.1 KiB
HTML
77 lines
3.1 KiB
HTML
<p>给出一个满足下述规则的二叉树：</p>
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<ol>
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<li><code>root.val == 0</code></li>
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<li>如果 <code>treeNode.val == x</code> 且 <code>treeNode.left != null</code>，那么 <code>treeNode.left.val == 2 * x + 1</code></li>
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<li>如果 <code>treeNode.val == x</code> 且 <code>treeNode.right != null</code>，那么 <code>treeNode.right.val == 2 * x + 2</code></li>
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</ol>
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<p>现在这个二叉树受到「污染」，所有的 <code>treeNode.val</code> 都变成了 <code>-1</code>。</p>
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<p>请你先还原二叉树，然后实现 <code>FindElements</code> 类：</p>
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<ul>
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<li><code>FindElements(TreeNode* root)</code> 用受污染的二叉树初始化对象，你需要先把它还原。</li>
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<li><code>bool find(int target)</code> 判断目标值 <code>target</code> 是否存在于还原后的二叉树中并返回结果。</li>
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</ul>
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<p> </p>
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<p><strong>示例 1：</strong></p>
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<p><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/11/16/untitled-diagram-4-1.jpg" style="height: 119px; width: 320px;"></strong></p>
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<pre><strong>输入：</strong>
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["FindElements","find","find"]
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[[[-1,null,-1]],[1],[2]]
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<strong>输出：</strong>
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[null,false,true]
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<strong>解释：</strong>
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FindElements findElements = new FindElements([-1,null,-1]);
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findElements.find(1); // return False
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findElements.find(2); // return True </pre>
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<p><strong>示例 2：</strong></p>
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<p><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/11/16/untitled-diagram-4.jpg" style="height: 198px; width: 400px;"></strong></p>
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<pre><strong>输入：</strong>
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["FindElements","find","find","find"]
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[[[-1,-1,-1,-1,-1]],[1],[3],[5]]
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<strong>输出：</strong>
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[null,true,true,false]
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<strong>解释：</strong>
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FindElements findElements = new FindElements([-1,-1,-1,-1,-1]);
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findElements.find(1); // return True
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findElements.find(3); // return True
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findElements.find(5); // return False</pre>
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<p><strong>示例 3：</strong></p>
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<p><strong><img alt="" src="https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/11/16/untitled-diagram-4-1-1.jpg" style="height: 274px; width: 306px;"></strong></p>
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<pre><strong>输入：</strong>
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["FindElements","find","find","find","find"]
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[[[-1,null,-1,-1,null,-1]],[2],[3],[4],[5]]
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<strong>输出：</strong>
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[null,true,false,false,true]
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<strong>解释：</strong>
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FindElements findElements = new FindElements([-1,null,-1,-1,null,-1]);
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findElements.find(2); // return True
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findElements.find(3); // return False
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findElements.find(4); // return False
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findElements.find(5); // return True
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</pre>
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<p> </p>
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<p><strong>提示：</strong></p>
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<ul>
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<li><code>TreeNode.val == -1</code></li>
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<li>二叉树的高度不超过 <code>20</code></li>
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<li>节点的总数在 <code>[1, 10^4]</code> 之间</li>
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<li>调用 <code>find()</code> 的总次数在 <code>[1, 10^4]</code> 之间</li>
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<li><code>0 <= target <= 10^6</code></li>
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</ul>
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