Solved Arai60/22. Generate Parentheses #52
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
oda
reviewed
Dec 26, 2025
| return list(parentheses) | ||
| ``` | ||
|
|
||
| - と思ったが(())(())のような部分的に囲むやつが考慮できていないので失敗 |
There was a problem hiding this comment.
こういう風にしたいならば、はじめの括弧と対応するやつは必ずあるはずなので、
(X)Y
と分ければいいですね。
Owner
Author
There was a problem hiding this comment.
どういう実装をイメージされているんでしょうか？
再帰だとできないのかなと思ったんですが、
There was a problem hiding this comment.
ご参考リンクです。
olsen-blue/Arai60#54 (comment)
| ```python | ||
| class Solution: | ||
| def generateParenthesis(self, n: int) -> List[str]: | ||
| if n == 1: |
| - 時間計算量：O(n^n) | ||
| - 各層の計算量が<2k C k | ||
| - 2k C k < k^k なので大体このくらい？ | ||
| - 空間計算量：O(n^n) |
Owner
Author
There was a problem hiding this comment.
ですね
下でもう少し正しい見積もりをしてみています
tokuhirat
reviewed
Jan 5, 2026
| parentheses = set() | ||
| parenthesis_opened_closed = [("", 0, 0)] | ||
| while parenthesis_opened_closed: | ||
| parenthesis, opened, closed = parenthesis_opened_closed.pop() |
There was a problem hiding this comment.
opened で開き括弧の数を表しているのは少しわかりにくいと思いました。自分で書くなら num_opens にします。
tokuhirat
reviewed
Jan 5, 2026
| if opened == n: | ||
| new_parenthesis = parenthesis + (opened - closed) * ")" | ||
| if new_parenthesis not in parentheses: | ||
| parentheses.add(new_parenthesis) |
tokuhirat
reviewed
Jan 5, 2026
| parentheses_and_openings = [("", 0)] | ||
| for opened in range(1, n + 1): | ||
| new_parentheses_and_openings = [] | ||
| for parenthesis, opening in parentheses_and_openings: |
There was a problem hiding this comment.
opened はこれまでに使った開き括弧の数で、opening はまだ対応する閉じ括弧がない開き括弧の数ということですよね。少し読み取りにくく感じました。下で書かれているようにこれまでに使った開き・閉じ括弧の数を考えた方がシンプルだと思いました。
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
問題：https://leetcode.com/problems/generate-parentheses/description/