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29 lines
1.4 KiB
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29 lines
1.4 KiB
HTML
<p>Given the <code>root</code> of a binary tree, construct a string consisting of parenthesis and integers from a binary tree with the preorder traversal way, and return it.</p>
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<p>Omit all the empty parenthesis pairs that do not affect the one-to-one mapping relationship between the string and the original binary tree.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/05/03/cons1-tree.jpg" style="width: 292px; height: 301px;" />
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<pre>
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<strong>Input:</strong> root = [1,2,3,4]
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<strong>Output:</strong> "1(2(4))(3)"
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<strong>Explanation:</strong> Originally, it needs to be "1(2(4)())(3()())", but you need to omit all the unnecessary empty parenthesis pairs. And it will be "1(2(4))(3)"
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</pre>
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<p><strong>Example 2:</strong></p>
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<img alt="" src="https://assets.leetcode.com/uploads/2021/05/03/cons2-tree.jpg" style="width: 207px; height: 293px;" />
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<pre>
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<strong>Input:</strong> root = [1,2,3,null,4]
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<strong>Output:</strong> "1(2()(4))(3)"
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<strong>Explanation:</strong> Almost the same as the first example, except we cannot omit the first parenthesis pair to break the one-to-one mapping relationship between the input and the output.
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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, 10<sup>4</sup>]</code>.</li>
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<li><code>-1000 <= Node.val <= 1000</code></li>
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</ul>
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