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40 lines
1.1 KiB
HTML
40 lines
1.1 KiB
HTML
<p>给定一个二叉树，判断它是否是高度平衡的二叉树。</p>
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<p>本题中，一棵高度平衡二叉树定义为：</p>
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<blockquote>
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<p>一个二叉树<em>每个节点 </em>的左右两个子树的高度差的绝对值不超过 1 。</p>
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</blockquote>
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<p> </p>
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<p><strong>示例 1：</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/10/06/balance_1.jpg" style="width: 342px; height: 221px;" />
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<pre>
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<strong>输入：</strong>root = [3,9,20,null,null,15,7]
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<strong>输出：</strong>true
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</pre>
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<p><strong>示例 2：</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2020/10/06/balance_2.jpg" style="width: 452px; height: 301px;" />
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<pre>
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<strong>输入：</strong>root = [1,2,2,3,3,null,null,4,4]
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<strong>输出：</strong>false
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</pre>
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<p><strong>示例 3：</strong></p>
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<pre>
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<strong>输入：</strong>root = []
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<strong>输出：</strong>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>树中的节点数在范围 <code>[0, 5000]</code> 内</li>
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<li><code>-10<sup>4</sup> <= Node.val <= 10<sup>4</sup></code></li>
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</ul>
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