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36 lines
1.3 KiB
HTML
36 lines
1.3 KiB
HTML
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<p>给你一个二叉树的根节点 <code>root</code>。设根节点位于二叉树的第 <code>1</code> 层，而根节点的子节点位于第 <code>2</code> 层，依此类推。</p>
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<p>请返回层内元素之和 <strong>最大</strong> 的那几层（可能只有一层）的层号，并返回其中 <strong>最小</strong> 的那个。</p>
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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/2019/08/17/capture.jpeg" style="height: 175px; width: 200px;" /></strong></p>
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<pre>
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<strong>输入：</strong>root = [1,7,0,7,-8,null,null]
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<strong>输出：</strong>2
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<strong>解释：</strong>
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第 1 层各元素之和为 1，
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第 2 层各元素之和为 7 + 0 = 7，
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第 3 层各元素之和为 7 + -8 = -1，
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所以我们返回第 2 层的层号，它的层内元素之和最大。
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</pre>
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<p><strong>示例 2：</strong></p>
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<pre>
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<strong>输入：</strong>root = [989,null,10250,98693,-89388,null,null,null,-32127]
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<strong>输出：</strong>2
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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<meta charset="UTF-8" /> <code>[1, 10<sup>4</sup>]</code>范围内<meta charset="UTF-8" /></li>
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<li><code>-10<sup>5</sup> <= Node.val <= 10<sup>5</sup></code></li>
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</ul>
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