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37 lines
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37 lines
1.5 KiB
HTML
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<p>给定一个二叉树的根节点 <code>root</code> ，和一个整数 <code>targetSum</code> ，求该二叉树里节点值之和等于 <code>targetSum</code> 的 <strong>路径</strong> 的数目。</p>
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<p><strong>路径</strong> 不需要从根节点开始，也不需要在叶子节点结束，但是路径方向必须是向下的（只能从父节点到子节点）。</p>
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<p> </p>
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<p><strong>示例 1：</strong></p>
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<p><img src="https://assets.leetcode.com/uploads/2021/04/09/pathsum3-1-tree.jpg" style="width: 452px; " /></p>
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<pre>
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<strong>输入：</strong>root = [10,5,-3,3,2,null,11,3,-2,null,1], targetSum = 8
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<strong>输出：</strong>3
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<strong>解释：</strong>和等于 8 的路径有 3 条，如图所示。
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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 = [5,4,8,11,null,13,4,7,2,null,null,5,1], targetSum = 22
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<strong>输出：</strong>3
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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>二叉树的节点个数的范围是 <code>[0,1000]</code></li>
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<li><meta charset="UTF-8" /><code>-10<sup><span style="font-size: 9.449999809265137px;">9</span></sup> <= Node.val <= 10<sup><span style="font-size: 9.449999809265137px;">9</span></sup></code> </li>
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<li><code>-1000 <= targetSum <= 1000</code> </li>
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</ul>
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<p> </p>
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<p><meta charset="UTF-8" />注意：本题与主站 437 题相同：<a href="https://leetcode-cn.com/problems/path-sum-iii/">https://leetcode-cn.com/problems/path-sum-iii/</a></p>
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