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28 lines
960 B
HTML
28 lines
960 B
HTML
<p>Given the <code>root</code> of a binary tree, return <em>the sum of all left leaves.</em></p>
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<p>A <strong>leaf</strong> is a node with no children. A <strong>left leaf</strong> is a leaf that is the left child of another node.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/04/08/leftsum-tree.jpg" style="width: 277px; height: 302px;" />
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<pre>
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<strong>Input:</strong> root = [3,9,20,null,null,15,7]
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<strong>Output:</strong> 24
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<strong>Explanation:</strong> There are two left leaves in the binary tree, with values 9 and 15 respectively.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> root = [1]
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<strong>Output:</strong> 0
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</pre>
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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>The number of nodes in the tree is in the range <code>[1, 1000]</code>.</li>
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<li><code>-1000 <= Node.val <= 1000</code></li>
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</ul>
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