98 validate binary search tree - #28
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miyataka
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Jul 26, 2026
| if node.left is None and node.right is None: | ||
| return True, node.val, node.val | ||
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| is_left_valid, left_min, left_max = _is_valid_bst_sub(node.left) |
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is_left_validがfalseな時点でearly returnもできますね．
ただ，現状のコードもこれはこれで綺麗なコードだと思います．
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ありがとうございます。そうすることで再起呼び出し回数を減らせますね。
nodchip
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Jul 30, 2026
| left_valid, left_min, left_max = results[node.left] | ||
| right_valid, right_min, right_max = results[node.right] | ||
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| results[node] = ( |
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left_max < node.val < right_min を満たさない場合、このタイミングで return False したほうがシンプルになると思いました。
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この問題：https://leetcode.com/problems/validate-binary-search-tree/
次の問題：https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/