Merge branch 'master' into issue/logistic_regression

Author: cclauss

.devcontainer/README.md

@@ -13,14 +13,15 @@ This is **Devcontainer** configuration to provide a consistent development envir
 
 ## Usage
 
-1. Install [**Docker** ](https://www.docker.com/get-started/) and [**Visual Studio Code**](https://code.visualstudio.com/)
+1. Install [**Docker**](https://www.docker.com/get-started/) and [**Visual Studio Code**](https://code.visualstudio.com/)
 2. Install the **Remote - Containers** extension in VS Code
 
     - Do `CTRL+P`, paste this command and press `Enter`
 
         ```shell
         ext install ms-vscode-remote.remote-containers
         ```
+
 3. Open this repository in VS Code
 4. When prompted, click **"Reopen in Container"**
 5. Wait for the environment to build and initialize

.devcontainer/devcontainer.json

@@ -1,17 +1,25 @@
 {
 	"name": "Python 3",
-	"build": {
-		"dockerfile": "Dockerfile",
-		"context": "..",
-		"args": {
-			// Update 'VARIANT' to pick a Python version: 3, 3.11, 3.10, 3.9, 3.8
-			// Append -bullseye or -buster to pin to an OS version.
-			// Use -bullseye variants on local on arm64/Apple Silicon.
-			"VARIANT": "3.13-bookworm"
-		}
-	},
 
-	"postCreateCommand": "zsh .devcontainer/post_install",
+	// Use a prebuilt dev container image instead of building from a local
+	// Dockerfile. The repo migrated its dependencies to pyproject.toml, so the
+	// old Dockerfile's `COPY requirements.txt` step no longer had a file to copy
+	// and the image build failed. The upstream images already ship Python + a
+	// full toolchain, so pulling one is both faster and less to maintain.
+	//
+	// This repo tracks the latest-and-greatest CPython on the newest stable
+	// Debian. Images are published per CPython minor version on Debian 13
+	// "Trixie" (3.11-trixie ... 3.14-trixie); bump this to the newest available
+	// when a new stable CPython ships.
+	// NOTE: these images do not publish free-threaded (`t`) variants, so 3.14t
+	// cannot be selected via the tag alone -- but the repo's `.python-version`
+	// pins 3.14t, and `uv run`/`uv sync` in the container honor it, so uv gives
+	// contributors free-threaded 3.14t regardless of the base tag.
+	"image": "mcr.microsoft.com/devcontainers/python:latest",
+
+	// Install the tools post_install and CI expect (pre-commit + ruff), plus uv
+	// for the free-threaded workflow above, then run the existing setup script.
+	"postCreateCommand": "pipx install pre-commit ruff uv && zsh .devcontainer/post_install",
 
 	// Configure tool-specific properties.
 	"customizations": {
@@ -20,26 +28,30 @@
 			// Set *default* container specific settings.json values on container create.
 			"settings": {
 				"python.defaultInterpreterPath": "/usr/local/bin/python",
-				"python.linting.enabled": true,
-				"python.formatting.blackPath": "/usr/local/py-utils/bin/black",
-				"python.linting.mypyPath": "/usr/local/py-utils/bin/mypy",
+				// Formatting/linting is handled by Ruff (matches pre-commit and CI).
+				"editor.formatOnSave": true,
+				"[python]": {
+					"editor.defaultFormatter": "charliermarsh.ruff",
+					"editor.codeActionsOnSave": {
+						"source.fixAll": "explicit",
+						"source.organizeImports": "explicit"
+					}
+				},
 				"terminal.integrated.defaultProfile.linux": "zsh"
 			},
 
 			// Add the IDs of extensions you want installed when the container is created.
 			"extensions": [
 				"ms-python.python",
-				"ms-python.vscode-pylance"
+				"ms-python.vscode-pylance",
+				"charliermarsh.ruff"
 			]
 		}
 	},
 
 	// Use 'forwardPorts' to make a list of ports inside the container available locally.
 	// "forwardPorts": [],
 
-	// Use 'postCreateCommand' to run commands after the container is created.
-	// "postCreateCommand": "pip3 install --user -r requirements.txt",
-
 	// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
 	"remoteUser": "vscode"
 }

.github/dependabot.yml

@@ -6,3 +6,5 @@ updates:
     directory: "/"
     schedule:
       interval: "daily"
+    cooldown:
+      default-days: 7

.github/pull_request_template.md

@@ -1,21 +1,20 @@
-### Describe your change:
-
-
+### Describe your change
 
 * [ ] Add an algorithm?
 * [ ] Fix a bug or typo in an existing algorithm?
 * [ ] Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
 * [ ] Documentation change?
 
-### Checklist:
+### Checklist
+
 * [ ] I have read [CONTRIBUTING.md](https://github.com/TheAlgorithms/Python/blob/master/CONTRIBUTING.md).
 * [ ] This pull request is all my own work -- I have not plagiarized.
 * [ ] I know that pull requests will not be merged if they fail the automated tests.
-* [ ] This PR only changes one algorithm file.  To ease review, please open separate PRs for separate algorithms.
+* [ ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
 * [ ] All new Python files are placed inside an existing directory.
 * [ ] All filenames are in all lowercase characters with no spaces or dashes.
 * [ ] All functions and variable names follow Python naming conventions.
 * [ ] All function parameters and return values are annotated with Python [type hints](https://docs.python.org/3/library/typing.html).
 * [ ] All functions have [doctests](https://docs.python.org/3/library/doctest.html) that pass the automated testing.
 * [ ] All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
-* [ ] If this pull request resolves one or more open issues then the description above includes the issue number(s) with a [closing keyword](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue): "Fixes #ISSUE-NUMBER".
+* [ ] If this pull request resolves one or more open issues, then the description above includes the issue number(s) with a [closing keyword](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue): "Fixes #ISSUE-NUMBER".

.github/skills/code-review/SKILL.md

@@ -0,0 +1,95 @@
+# Skill: Code review for TheAlgorithms/Python
+
+Review a pull request against the rules already written in
+[`CONTRIBUTING.md`](../../../CONTRIBUTING.md). The goal is a review that any
+reviewer (human or AI) can run the same way every time, and that produces a clear,
+kind, actionable verdict.
+
+## How to run this skill
+
+Read the PR diff, then work through the four `CONTRIBUTING.md` sections in order
+and emit the fixed output shape below. Cite the exact rule you are applying and
+suggest the fix — never just "rejected".
+
+### 1. Before contributing / Is this an algorithm?
+
+- [ ] The change adds, fixes, or documents **one algorithm** — not multiple, and
+      not both code and doctest changes in the same PR.
+- [ ] It is a genuine algorithm or data structure (see the *What is an Algorithm?*
+      section), not a script, snippet, how-to-use for an existing API, or exercise
+      dump.
+- [ ] It is **not already in the repository** (search the existing directories).
+- [ ] **No earlier open PR** already does the same thing — link it if one exists.
+- [ ] Properly attributed — no plagiarism; prior sources credited.
+
+### 2. Coding Style
+
+- [ ] `from __future__ import annotations` is not needed because this repo only uses
+      the latest version of CPython.
+- [ ] File and directory names are lowercase, use underscores, and land inside an
+      existing directory.
+- [ ] Public functions/classes have **type hints**.
+- [ ] Public functions have **doctests that actually pass**.
+- [ ] Descriptive variable and function names (no single letters where a word helps).
+- [ ] Code is formatted and lint-clean (`ruff`, `pre-commit`).
+
+> **Optional hint:** When a PR hand-writes a simple class that is mostly a
+> bundle of fields (a manual `__init__` plus `__repr__`/`__eq__`), it is worth
+> **suggesting** `from typing import NamedTuple` or
+> `from dataclasses import dataclass` where they would simplify the code. These
+> are underutilized tools that our contributors would benefit from using where
+> they make sense. Offer it as an optional improvement, not a blocker — do not
+> request changes solely because a class was written the longhand way.
+
+#### When a PR fails `ruff check`
+
+Don't just report the failure — try the mechanical fixes and recommend the one
+that works, in this order:
+
+1. Run `ruff check --fix file_path.py`. If that makes the file pass, recommend
+   that solution — these are the fixes `ruff` considers **safe**.
+2. If it still fails, run `ruff check --fix --unsafe-fixes file_path.py`. If that
+   makes the file pass **and** the resulting diff is genuinely safe (it preserves
+   behavior — review it, don't trust it blindly), recommend that solution and note
+   that it required `--unsafe-fixes`.
+3. If neither passes, or the unsafe fix would change behavior, describe the
+   remaining rule violations and the manual change the author needs to make.
+
+Always quote the exact rule code(s) `ruff` reports (e.g., `ruff rule UP047`,
+`ruff rule RUF100`) so the author can run those commands to read the rules being
+flagged. Also, paste the concrete command you ran.
+
+### 3. Other Requirements for Submissions
+
+- [ ] At least one **Wikipedia (or equivalent) URL** documenting the algorithm.
+- [ ] Docstring explains what the function does and its parameters/returns.
+- [ ] No unnecessary third-party dependencies.
+
+### 4. Verdict — fixed output shape
+
+Emit exactly these headings so reviews are comparable and easy to automate:
+
+```text
+### Is this an algorithm? — <yes/no + one-line why>
+### Duplicate / prior-art check — <#NNNN | none found>
+### Coding style — <pass | issues: …>
+### Other requirements (doctests, type hints, descriptive names, Wikipedia URL) — <pass | issues: …>
+### Verdict — <approve | request changes | close> + one-line reason
+```
+
+## Tone
+
+Be specific and kind. Point at the exact `CONTRIBUTING.md` rule and offer the fix
+rather than a bare rejection — first-time and Hacktoberfest contributors are more
+likely to come back and improve the PR when the path forward is clear.
+
+## Map findings to labels
+
+Where a finding matches an existing label, name it so the review lines up with the
+maintenance/cleanup tooling:
+
+- missing/failing doctests → `require tests`
+- missing type hints → `require type hints`
+- non-descriptive names → `require descriptive names`
+- CI red → `tests are failing`
+- otherwise ready for a maintainer → `awaiting reviews`

.github/skills/new-pull-request/SKILL.md

@@ -0,0 +1,75 @@
+# Skill: New pull request for TheAlgorithms/Python
+
+Create a new pull request using the rules already written in
+[`CONTRIBUTING.md`](../../../CONTRIBUTING.md). The goal is that creating a new
+pull request (human or AI) can run the same way every time, and that produces a
+clear, kind, tested, type-hinted, mergeable contribution.
+
+## How to run this skill
+
+Make sure that the local `master` branch is synced with `upstream/master` before
+creating a new pull request.
+
+Create a new clearly named branch for the pull request. Pull request changes must
+not be made or submitted on the `master` branch.
+
+Never hand-edit or revert the `uv.lock` file. If you add a legitimate
+dependency, let the `uv-lock` pre-commit hook regenerate it — do not touch it by
+hand. A hand-modified `uv.lock` makes the `algorithms-keeper` bot close the pull
+request as invalid, and even a repo maintainer cannot undo that.
+
+Always check at least one Markdown checkbox in the pull request description (the "Describe your change" section), or the
+`algorithms-keeper` bot will close the pull request as invalid — and it does
+this *before* a human reads the PR, so a genuinely good change gets closed for a
+formatting reason. This applies to **every** pull request, including CI, docs,
+and tooling changes that are not algorithms: tick the boxes that genuinely apply
+so the body is never submitted with all boxes empty. Any repo maintainer can
+undo this if you @mention them on the closed pull request, but re-opening is
+often unreliable, so it is far better to get it right the first time.
+
+### 1. Before contributing / Is this an algorithm?
+
+- [ ] The change adds, fixes, or documents **one algorithm** — not multiple, and
+      not both code and doctest changes in the same PR.
+- [ ] It is a genuine algorithm or data structure (see the *What is an Algorithm?*
+      section), not a script, snippet, how-to-use for an existing API, or exercise
+      dump.
+- [ ] It is **not already in the repository** (search the existing directories).
+- [ ] **No earlier open PR** already does the same thing — link it if one exists.
+- [ ] Properly attributed — no plagiarism; prior sources credited.
+
+### 2. Coding Style
+
+- [ ] `from __future__ import annotations` is not needed because this repo only uses
+      the latest version of CPython.
+- [ ] File and directory names are lowercase, use underscores, and land inside an
+      existing directory.
+- [ ] Public functions/classes have **type hints**.
+- [ ] Public functions have **doctests that actually pass**.
+- [ ] Descriptive variable and function names (no single letters where a word helps).
+- [ ] For a simple class that is mostly a bundle of fields, **consider**
+      `from typing import NamedTuple` or `from dataclasses import dataclass`
+      instead of a hand-written `__init__`/`__repr__`/`__eq__`. These are
+      underutilized tools that make simple classes shorter and clearer — use
+      them where they genuinely simplify the code, not everywhere.
+- [ ] Code is formatted and lint-clean (`ruff`, `pre-commit`).
+- [ ] `DIRECTORY.md` and `README.md` are **not hand-edited** — the
+      `algorithms-keeper` bot regenerates them automatically after merge.
+
+### 3. Other Requirements for Submissions
+
+- [ ] At least one **Wikipedia (or equivalent) URL** documenting the algorithm.
+- [ ] Docstring explains what the function does and its parameters/returns.
+- [ ] No unnecessary third-party dependencies.
+
+## Before you click "Create pull request"
+
+This is the final gate. Do not open the pull request until every item here is true:
+
+- [ ] At least one Markdown checkbox in the PR description is checked. **Verify
+      this by re-reading the rendered body** — if every box is still `- [ ]`, the
+      `algorithms-keeper` bot will auto-close the PR before any human sees it.
+      Check the boxes that genuinely apply to this change; never submit an
+      all-empty checklist, even for a CI, docs, or tooling PR.
+- [ ] The branch is not `master`, and `master` is synced with `upstream/master`.
+- [ ] `uv.lock` was not hand-edited.