feat: add solution and documentation for LeetCode 66. Plus One#241
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myoshi2891
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Jan 25, 2026
- Added Python and TypeScript solutions in IPYNB format
- Added comprehensive README.md in Japanese
- Added interactive README_react.html documentation
- Added Python and TypeScript solutions in IPYNB format - Added comprehensive README.md in Japanese - Added interactive README_react.html documentation
📝 WalkthroughSummary by CodeRabbitリリースノート
✏️ Tip: You can customize this high-level summary in your review settings. WalkthroughLeetCode 66（プラスワン）問題の包括的なドキュメンテーションとリファレンス実装を新規追加。Python、TypeScriptの実装ノートブック、詳細なREADMEドキュメント、およびReact対応のインタラクティブなHTML説明資料で構成。 Changes
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~25 minutes Poem
🚥 Pre-merge checks | ✅ 3✅ Passed checks (3 passed)
✏️ Tip: You can configure your own custom pre-merge checks in the settings. Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
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Actionable comments posted: 6
🤖 Fix all issues with AI agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet
4.5/PlusOne_python.ipynb:
- Around line 192-199: The input validation loop over digits incorrectly accepts
booleans because isinstance(digit, int) returns True for bool; update the check
in the loop that currently reads "for i, digit in enumerate(digits):" to exclude
bools—e.g., replace the isinstance(digit, int) check with a strict type check
such as type(digit) is int or add an extra condition like isinstance(digit, int)
and not isinstance(digit, bool) so that True/False are rejected before the range
check in the function handling digits (the loop using variables i and digit).
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet
4.5/PlusOne_typescript.ipynb:
- Around line 23-26: The documentation claim that `number[]` guarantees digits
0–9 is incorrect; either change the doc line ("型定義で 0-9 の範囲を保証") to state that
TypeScript cannot enforce numeric ranges and runtime validation is required, or
add runtime checks in the implementation (e.g., in the function handling the
input—referenced as the `readonly number[]` argument handling and the logic
around lines 76–79) that iterate the input digits and throw or return an error
if any element is not an integer in [0,9]; update tests/comments accordingly to
reflect the chosen approach.
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README_react.html:
- Around line 8-31: The HTML includes remote CDN assets for Tailwind (the
<script src="https://cdn.tailwindcss.com"></script>), Google Fonts link tags,
and Prism.js CSS links without Subresource Integrity or production-optimized
builds; update these tags to use SRI and crossorigin attributes (add
integrity="..." and crossorigin="anonymous" to each CDN link), replace any
dev/standalone builds with their production/minified URLs (use
prism-tomorrow.min.css and prod Tailwind build or a locally built CSS), and
preferably vendor the built assets (prebuild Tailwind and Prism during your
build process and serve locally) to avoid using babel-standalone or runtime CDN
transforms; ensure the same changes are applied to the other occurrences of
these tags referenced in the diff (the Tailwind script tag, the Google
Fonts/preconnect links, and the Prism CSS link elements).
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README.md:
- Around line 319-325: 現在の入力検証で isinstance(digit, int) が True/False
を許してしまうため、ループ内の型チェックを bool を明示的に除外するよう修正してください（参照箇所: 変数 digits を走査している for
ループ、エラーは TypeError を投げる処理）。たとえば type(digit) is int を使するか、isinstance(digit, int)
and not isinstance(digit, bool) のようにして bool を弾き、既存の ValueError
チェックやエラーメッセージ（f"Element at index {i} must be an integer"）はそのまま維持してください。
- Around line 556-570: Update the LeetCode Python version note in the Q6 section
(the paragraph stating "LeetCodeはPython 3.11+なので `list[int]` が標準。") to reflect
the current environment: either change the explicit version to "Python 3.14" or
remove the specific version and make it version-agnostic by saying "`list[int]`
is available in Python 3.9+ (PEP 585) and is the recommended annotation"; ensure
the surrounding explanation for def plusOne(...) and the examples using
`list[int]` vs `List[int]` remain consistent with that change.
- Around line 348-358: Update the README text to avoid absolute performance
claims about "[1, *digits]" vs "[1] + digits": remove the statements about fixed
"copy counts" and "約10-20%の高速化", and replace them with a note that performance
depends on input size (small lists may show a modest advantage for the spread
form while large lists are similar) and that readability should guide choice;
reference the two forms "[1, *digits]" and "[1] + digits" in the new wording so
readers can locate the examples.
| " for i, digit in enumerate(digits):\n", | ||
| " if not isinstance(digit, int):\n", | ||
| " raise TypeError(f\"Element at index {i} must be an integer\")\n", | ||
| " \n", | ||
| " if not 0 <= digit <= 9:\n", | ||
| " raise ValueError(\n", | ||
| " f\"Element at index {i} ({digit}) must be in range [0, 9]\"\n", | ||
| " )\n", |
There was a problem hiding this comment.
🧩 Analysis chain
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find . -name "PlusOne_python.ipynb" -type fRepository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 166
🏁 Script executed:
wc -l "./Algorithm/Other/leetcode/66. Plus One/Claude Sonnet 4.5/PlusOne_python.ipynb"Repository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 170
🏁 Script executed:
cat -n "./Algorithm/Other/leetcode/66. Plus One/Claude Sonnet 4.5/PlusOne_python.ipynb" | sed -n '180,210p'Repository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 1564
🏁 Script executed:
python3 << 'EOF'
# Verify if bool is instance of int in Python
print("isinstance(True, int):", isinstance(True, int))
print("isinstance(False, int):", isinstance(False, int))
print("isinstance(True, bool):", isinstance(True, bool))
print("isinstance(False, bool):", isinstance(False, bool))
# Test the validation logic
digit = True
if not isinstance(digit, int):
print("Would raise TypeError for True")
else:
print("True passes isinstance(digit, int) check")
# Test the proposed fix
digit = True
if not isinstance(digit, int) or isinstance(digit, bool):
print("With fix: True would raise TypeError")
else:
print("With fix: True would still pass")
EOFRepository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 281
bool が整数として通過してしまう入力検証
isinstance(digit, int) を使用していますが、Pythonでは bool は int のサブクラスであるため、True と False が整数として許可されてしまいます。より厳密な型検証が必要な場合は bool を除外してください。
修正案
- if not isinstance(digit, int):
+ if not isinstance(digit, int) or isinstance(digit, bool):
raise TypeError(f"Element at index {i} must be an integer")🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/PlusOne_python.ipynb
around lines 192 - 199, The input validation loop over digits incorrectly
accepts booleans because isinstance(digit, int) returns True for bool; update
the check in the loop that currently reads "for i, digit in enumerate(digits):"
to exclude bools—e.g., replace the isinstance(digit, int) check with a strict
type check such as type(digit) is int or add an extra condition like
isinstance(digit, int) and not isinstance(digit, bool) so that True/False are
rejected before the range check in the function handling digits (the loop using
variables i and digit).
| "### TypeScript特有の考慮点\n", | ||
| "- **型推論**: `number[]` の厳密な型定義で0-9の範囲を保証\n", | ||
| "- **readonly**: 引数を `readonly number[]` にすると副作用を防げる（要新配列生成）\n", | ||
| "- **型ガード**: 実行時の配列要素検証\n", |
There was a problem hiding this comment.
🧩 Analysis chain
🏁 Script executed:
find . -name "PlusOne_typescript.ipynb" -type fRepository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 170
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cat -n "./Algorithm/Other/leetcode/66. Plus One/Claude Sonnet 4.5/PlusOne_typescript.ipynb"Repository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 9974
number[] 型では 0～9 の値域を保証できない
24 行目の「型定義で 0-9 の範囲を保証」は TypeScript の型システムでは実現できません。現在の実装（76～79 行目）は配列の存在確認のみで、各要素の値域チェックがありません。ランタイム検証を追加するか、ドキュメントを「型では保証できず、ランタイム検証が必要」と修正してください。
値域検証の追加例
function plusOne(digits: number[]): number[] {
// 型ガード: 配列の検証
if (!Array.isArray(digits) || digits.length === 0) {
throw new TypeError('Input must be a non-empty array');
}
+ for (const [i, d] of digits.entries()) {
+ if (!Number.isInteger(d) || d < 0 || d > 9) {
+ throw new TypeError(`Element at index ${i} must be an integer in [0, 9]`);
+ }
+ }Also applies to: 75-90
🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet
4.5/PlusOne_typescript.ipynb around lines 23 - 26, The documentation claim that
`number[]` guarantees digits 0–9 is incorrect; either change the doc line ("型定義で
0-9 の範囲を保証") to state that TypeScript cannot enforce numeric ranges and runtime
validation is required, or add runtime checks in the implementation (e.g., in
the function handling the input—referenced as the `readonly number[]` argument
handling and the logic around lines 76–79) that iterate the input digits and
throw or return an error if any element is not an integer in [0,9]; update
tests/comments accordingly to reflect the chosen approach.
| <!-- Tailwind CSS --> | ||
| <script src="https://cdn.tailwindcss.com"></script> | ||
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| <!-- Google Fonts --> | ||
| <link rel="preconnect" href="https://fonts.googleapis.com" /> | ||
| <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin /> | ||
| <link | ||
| href="https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700;800&family=JetBrains+Mono:wght@400;600&family=Source+Code+Pro:wght@400;600;700&display=swap" | ||
| rel="stylesheet" | ||
| /> | ||
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| <!-- Prism.js CSS --> | ||
| <link | ||
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| href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/themes/prism-tomorrow.min.css" | ||
| /> | ||
| <link | ||
| rel="stylesheet" | ||
| href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/plugins/line-numbers/prism-line-numbers.min.css" | ||
| /> | ||
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| href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.29.0/plugins/toolbar/prism-toolbar.min.css" | ||
| /> |
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🧹 Nitpick | 🔵 Trivial
CDN アセットに SRI/本番ビルドが無く供給チェーンリスク
公開配布やホスティング前提なら、CDN 取得の React/Tailwind/Prism/Babel には integrity を付与し、可能なら production ビルド＋事前ビルド（Babel standalone 回避）で安全性と性能を上げることを推奨します。
Also applies to: 926-942
🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README_react.html
around lines 8 - 31, The HTML includes remote CDN assets for Tailwind (the
<script src="https://cdn.tailwindcss.com"></script>), Google Fonts link tags,
and Prism.js CSS links without Subresource Integrity or production-optimized
builds; update these tags to use SRI and crossorigin attributes (add
integrity="..." and crossorigin="anonymous" to each CDN link), replace any
dev/standalone builds with their production/minified URLs (use
prism-tomorrow.min.css and prod Tailwind build or a locally built CSS), and
preferably vendor the built assets (prebuild Tailwind and Prism during your
build process and serve locally) to avoid using babel-standalone or runtime CDN
transforms; ensure the same changes are applied to the other occurrences of
these tags referenced in the diff (the Tailwind script tag, the Google
Fonts/preconnect links, and the Prism CSS link elements).
| for i, digit in enumerate(digits): | ||
| if not isinstance(digit, int): | ||
| raise TypeError(f"Element at index {i} must be an integer") | ||
|
|
||
| if not 0 <= digit <= 9: | ||
| raise ValueError( | ||
| f"Element at index {i} ({digit}) must be in range [0, 9]" |
There was a problem hiding this comment.
🧩 Analysis chain
🏁 Script executed:
# First, let's find and check the file
find . -name "README.md" -path "*66. Plus One*" 2>/dev/null | head -5Repository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 155
🏁 Script executed:
# Check Python version and bool subclass relationship
python3 << 'EOF'
# Verify that bool is a subclass of int
print("bool is subclass of int:", issubclass(bool, int))
print("isinstance(True, int):", isinstance(True, int))
print("isinstance(False, int):", isinstance(False, int))
print("isinstance(True, bool):", isinstance(True, bool))
print("isinstance(1, bool):", isinstance(1, bool))
EOFRepository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 230
🏁 Script executed:
# Read the README.md file at the specified lines
sed -n '315,330p' "./Algorithm/Other/leetcode/66. Plus One/Claude Sonnet 4.5/README.md"Repository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 675
bool が整数として通ってしまう入力検証
Python では bool が int のサブクラスのため、isinstance(digit, int) だと True/False が許可されてしまいます。入力検証で bool を明示的に除外してください。
修正案
- if not isinstance(digit, int):
+ if not isinstance(digit, int) or isinstance(digit, bool):
raise TypeError(f"Element at index {i} must be an integer")🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README.md around
lines 319 - 325, 現在の入力検証で isinstance(digit, int) が True/False
を許してしまうため、ループ内の型チェックを bool を明示的に除外するよう修正してください（参照箇所: 変数 digits を走査している for
ループ、エラーは TypeError を投げる処理）。たとえば type(digit) is int を使するか、isinstance(digit, int)
and not isinstance(digit, bool) のようにして bool を弾き、既存の ValueError
チェックやエラーメッセージ（f"Element at index {i} must be an integer"）はそのまま維持してください。
| ### 2. スプレッド演算子によるリスト結合 | ||
|
|
||
| ```python | ||
| # 推奨: スプレッド演算子（Python 3.5+） | ||
| return [1, *digits] | ||
|
|
||
| # 非推奨: リスト結合（コピーが2回発生） | ||
| return [1] + digits | ||
| ``` | ||
|
|
||
| **効果**: メモリコピーの回数削減、約10-20%の高速化 |
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🧩 Analysis chain
🌐 Web query:
[1, *digits] vs [1] + digits Python performance benchmark
💡 Result:
For digits being a list, these two are usually very close in CPython performance:
a = [1, *digits](list display + starred-unpack)a = [1] + digits(list concatenation)
Why they’re close
- Starred-unpacking in list displays (introduced by PEP 448) compiles to bytecode that builds a list and then extends it (notably via
LIST_EXTEND). [1][2] +on lists creates a new list and copies elements from both operands (still linear time overall). List concatenation is generally described as linear in the total size. [3]
So both are effectively O(len(digits)) work plus allocation/copying.
When one can win
- If
digitsis already a list,[1] + digitscan be slightly faster in some builds because it can allocate the final size in one go and copy. (Microbench-dependent.) - If
digitsis not a list (e.g., a generator/range/tuple),[1] + digitseither errors (non-list) or forces a conversion, while[1, *digits]works with any iterable (but may pay iteration/conversion costs). PEP 448 explicitly defines this iterable-unpacking behavior. [1]
Benchmark it on your Python (recommended)
import timeit
setup = "digits = list(range(1000))"
print(timeit.timeit("[1, *digits]", setup=setup, number=200_000))
print(timeit.timeit("[1] + digits", setup=setup, number=200_000))If you tell me your Python version (e.g., 3.10/3.11/3.12/3.13) and typical len(digits), I can suggest a more representative benchmark (and pitfalls to avoid).
Sources: PEP 448 starred-unpacking in displays [1]; CPython bytecode LIST_EXTEND used to build lists [2]; list concatenation time complexity discussion [3].
[1] (peps.python.org)
[2] (docs.python.org)
[3] (geeksforgeeks.org)
Citations:
- 1: https://peps.python.org/pep-0448/?utm_source=openai
- 2: https://docs.python.org/3.11/library/dis.html?utm_source=openai
- 3: https://www.geeksforgeeks.org/python/difference-between-and-append-in-python/?utm_source=openai
🌐 Web query:
CPython list unpacking operator performance vs concatenation
💡 Result:
In CPython, for two existing lists:
a + bis usually fastest because CPython’slist_concatallocates exactly one new list of sizelen(a)+len(b)and then copies references fromaandbinto it. [1][*a, *b]is compiled as “build a new list, then extend it for each*part” (CPython uses list-building opcodes likeLIST_EXTEND). Eachextendcan trigger its own growth/resize logic, so it commonly has a bit more overhead than a single dedicated concat. [2][3][4]
For more than two inputs, the trade-off changes:
- Repeated
+(e.g.a + b + c + d) is typically worst because it creates intermediate temporary lists at each+. [*a, *b, *c, *d]avoids those intermediate temporaries (still makes the final list), so it often wins versus chained+for many parts. The syntax/semantics come from PEP 448. [2]
If you don’t need a new list (you want to mutate in place), a.extend(b) / a += b is typically best (it grows a and copies in elements once). The underlying extend path tries to pre-grow based on an iterator length hint when available. [4]
Rule of thumb (CPython):
- New list from two lists: prefer
a + b. [1] - Combine many iterables into a new list: prefer
[*it1, *it2, ...](orlist(itertools.chain.from_iterable(...))when inputs are dynamic). - Mutate an existing list: prefer
extend/+=. [4]
Sources: [1] CPython list_concat_lock_held in Objects/listobject.c (prealloc + copy). [2] PEP 448 (unpacking in list displays). [3] dis docs for LIST_EXTEND (“Used to build lists”). [4] CPython list_extend_iter_lock_held / resize logic in Objects/listobject.c.
🏁 Script executed:
#!/bin/bash
# Let's create a simple benchmark to test both approaches
python3 << 'EOF'
import timeit
# Test with different input sizes
for size in [10, 100, 1000]:
digits = list(range(size))
# Approach 1: unpacking operator
t1 = timeit.timeit(lambda: [1, *digits], number=100000)
# Approach 2: concatenation
t2 = timeit.timeit(lambda: [1] + digits, number=100000)
diff_percent = ((t2 - t1) / t2) * 100 if t2 > 0 else 0
print(f"Size {size}:")
print(f" [1, *digits]: {t1:.4f}s")
print(f" [1] + digits: {t2:.4f}s")
print(f" Difference: {diff_percent:.1f}% (unpacking is {'faster' if t1 < t2 else 'slower'})")
print()
EOFRepository: myoshi2891/Algorithm-DataStructures-Math-SQL
Length of output: 395
[1, *digits] と [1] + digits の性能差は入力サイズに依存
「コピー回数」や「10–20%高速化」は絶対的ではありません。ベンチマークによると、サイズが小さい場合（10–100要素）は [1, *digits] がやや速いものの、大規模な入力ではほぼ同等です。性能を理由に一方を強く推奨するより、可読性で選択することをお勧めします。
文言の調整例
-# 非推奨: リスト結合（コピーが2回発生）
+# 参考: 実装差は小さいため可読性を優先して選択してよい
return [1] + digits
@@
-**効果**: メモリコピーの回数削減、約10-20%の高速化
+**効果**: 実装・入力サイズに依存するため、必要ならベンチマークで確認🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README.md around
lines 348 - 358, Update the README text to avoid absolute performance claims
about "[1, *digits]" vs "[1] + digits": remove the statements about fixed "copy
counts" and "約10-20%の高速化", and replace them with a note that performance depends
on input size (small lists may show a modest advantage for the spread form while
large lists are similar) and that readability should guide choice; reference the
two forms "[1, *digits]" and "[1] + digits" in the new wording so readers can
locate the examples.
| ### Q6: 型ヒント `List[int]` vs `list[int]` の使い分けは? | ||
|
|
||
| **A**: Python 3.9+では `list[int]` が推奨（PEP 585）: | ||
|
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||
| ```python | ||
| # Python 3.9+（推奨） | ||
| def plusOne(self, digits: list[int]) -> list[int]: | ||
|
|
||
| # Python 3.8以前（後方互換） | ||
| from typing import List | ||
| def plusOne(self, digits: List[int]) -> List[int]: | ||
| ``` | ||
|
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||
| LeetCodeはPython 3.11+なので `list[int]` が標準。 | ||
|
|
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🧩 Analysis chain
🌐 Web query:
LeetCode Python runtime version 2025 2026
💡 Result:
LeetCode’s official “Languages environment” page (updated Jan 6, 2026) lists:
- Python (legacy): 2.7.18
- Python3: 3.14 (this is what you typically want for LeetCode submissions) [1]
Source: LeetCode Help Center → “What are the environments for the programming languages?” [1]
References:
[1] (support.leetcode.com)
Citations:
LeetCode の Python バージョン表記を更新してください
ドキュメント内の「LeetCodeはPython 3.11+なので」という記載は不正確です。LeetCode の公式ページ（2026年1月6日更新）によると、現在の実行環境は Python 3.14 です。このため、記載内容を以下のいずれかで修正してください：
- 最新バージョン（3.14）に更新する
- バージョン非依存の表現にする（例：「
list[int]は Python 3.9+ で利用可能」のみに統一）
実行環境は定期的に更新されるため、具体的なバージョン番号を記載する場合は、公式ページで常に最新状態を確認することをお勧めします。
🤖 Prompt for AI Agents
In `@Algorithm/Other/leetcode/66`. Plus One/Claude Sonnet 4.5/README.md around
lines 556 - 570, Update the LeetCode Python version note in the Q6 section (the
paragraph stating "LeetCodeはPython 3.11+なので `list[int]` が標準。") to reflect the
current environment: either change the explicit version to "Python 3.14" or
remove the specific version and make it version-agnostic by saying "`list[int]`
is available in Python 3.9+ (PEP 585) and is the recommended annotation"; ensure
the surrounding explanation for def plusOne(...) and the examples using
`list[int]` vs `List[int]` remain consistent with that change.