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infはマジックナンバー感があるとの意見をみた。適当な変数に代入したほうがよさそう |
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generator使うとプロっぽくてかっこいい |
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私は、わりと inf でいいかなと思っています。(これ自体はどちらにしてもあんまり大きな話ではないです。) |
huyfififi
reviewed
Jul 24, 2025
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| 2回目。ほかの人のコードを見る。 | ||
| - これはとても勉強になる：https://github.com/quinn-sasha/leetcode/pull/27/files#r2200377284 | ||
| - in-order に探索する方法を知った：https://discord.com/channels/1084280443945353267/1192736784354918470/1234120299008491581 |
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BSTをin-order traversalすると昇順に並んだ数列が得られることを利用する問題はたまに見かけるような気がしますね。具体的にどこで出会ったかは思い出せませんが...
nodchip
reviewed
Jul 24, 2025
| if not (lower_bound < node.val < upper_bound): | ||
| return False | ||
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| is_left_valid = validate(node.left, lower_bound, node.val) |
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return validate(node.left, lower_bound, node.val) and validate(node.right, node.val, upper_bound) とすると、短絡評価で速くなる場合があると思います。
tokuhirat
reviewed
Jul 24, 2025
| 2回目。ほかの人のコードを見る。 | ||
| - これはとても勉強になる：https://github.com/quinn-sasha/leetcode/pull/27/files#r2200377284 | ||
| - in-order に探索する方法を知った：https://discord.com/channels/1084280443945353267/1192736784354918470/1234120299008491581 | ||
| - 以下は Gemini による回答 |
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これを見て何を思ったかや、再現できるように書き直したコードを書いていただけるとコメントしやすいと思います。
L27 にリストとありますが正しいでしょうか？
self.prev_val というようなインスタンス変数を使わない方法として、単に prev_val = float('-inf') として関数内関数で nonlocal prev_val と書くこともできますね。こうすることで isValidBST がスレッドセーフになると思います。
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https://leetcode.com/problems/validate-binary-search-tree/