Disallow search crawling

revert Update funnel configuration

.github/workflows/deploy-homelab.yml

@@ -1,4 +1,4 @@
-name: "Deploy to Homelab"
+name: "Deploy to birb co. production"
 
 on:
   push:
@@ -23,23 +23,21 @@ jobs:
 
     - name: Remove directory from server
       run: |
-        ssh -i ~/.ssh/id_ed25519 github@${{ vars.HOST }} << 'EOF'
-          rm -rf ~/homelab-static
+        ssh -i ~/.ssh/id_ed25519 ${{ vars.USERNAME }}@${{ vars.HOST }} << 'EOF'
+          rm -rf ~/homelab-dsa-tutoring
         EOF
 
     # Avoid needing to set up SSH access to GitHub for this user
     - name: Transfer repository files to server
       run: |
-        scp -i ~/.ssh/id_ed25519 -r ./* github@${{ vars.HOST }}:~/homelab-static
+        scp -i ~/.ssh/id_ed25519 -r ./* ${{ vars.USERNAME }}@${{ vars.HOST }}:~/homelab-dsa-tutoring
 
     - name: Deploy on server with Docker
       run: |
-        ssh -i ~/.ssh/id_ed25519 github@${{ vars.HOST }} << 'EOF'
-          cd ~/homelab-static
-          export TS_AUTHKEY=${{ secrets.TS_CONTAINER_AUTHKEY }}
+        ssh -i ~/.ssh/id_ed25519 ${{ vars.USERNAME }}@${{ vars.HOST }} << 'EOF'
+          cd ~/homelab-dsa-tutoring
+          export DOCKER_HOST=unix://$XDG_RUNTIME_DIR/docker.sock
           docker compose -f docker-compose.yml down
           docker compose -f docker-compose.yml up -d --build
         EOF
 
-
-

.gitignore

@@ -0,0 +1,179 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# UV
+#   Similar to Pipfile.lock, it is generally recommended to include uv.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#uv.lock
+
+# poetry
+#   Similar to Pipfile.lock, it is generally recommended to include poetry.lock in version control.
+#   This is especially recommended for binary packages to ensure reproducibility, and is more
+#   commonly ignored for libraries.
+#   https://python-poetry.org/docs/basic-usage/#commit-your-poetrylock-file-to-version-control
+#poetry.lock
+
+# pdm
+#   Similar to Pipfile.lock, it is generally recommended to include pdm.lock in version control.
+#pdm.lock
+#   pdm stores project-wide configurations in .pdm.toml, but it is recommended to not include it
+#   in version control.
+#   https://pdm.fming.dev/latest/usage/project/#working-with-version-control
+.pdm.toml
+.pdm-python
+.pdm-build/
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow and github.com/pdm-project/pdm
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
+
+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+# PyCharm
+#  JetBrains specific template is maintained in a separate JetBrains.gitignore that can
+#  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
+#  and can be added to the global gitignore or merged into this file.  For a more nuclear
+#  option (not recommended) you can uncomment the following to ignore the entire idea folder.
+#.idea/
+
+# Ruff stuff:
+.ruff_cache/
+
+# PyPI configuration file
+.pypirc
+
+.DS_Store
+
+# Generated build output
+public/

CLAUDE.md

@@ -0,0 +1,32 @@
+# homelab-dsa-tutoring
+
+## Overview
+
+This is a collection of Python projects for a tutoring side-gig focused on Data Structures and Algorithms (DSA).
+
+It was previously deployed to a personal homelab server as a Tailscale file server (see `.github/workflows/deploy-homelab.yml`). The workflow SCP'd the repo to the server and ran a Docker Compose stack that served the files.
+
+## Structure
+
+```
+shared/
+├── assignments/          # PDFs and other assignment materials
+└── notes-and-examples/   # Lesson files organized by date (YYYY.MM.DD)
+```
+
+Each lesson folder under `notes-and-examples/` contains one or more Python files used during the tutoring session.
+
+## Lessons
+
+| Date | Topics |
+|------|--------|
+| 2026.01.21 | Sorting algorithms (bubble sort, insertion sort) |
+| 2026.01.28 | Object references, shallow/deep copies, linked lists |
+| 2026.02.04 | Queue data structure |
+| 2026.02.11 | Stack data structure |
+
+## Notes
+
+- No external dependencies — pure Python, no `requirements.txt` needed.
+- Student homework submissions go to `me@bchen.dev`.
+- Lesson files often include skeleton classes with method stubs for students to implement.

Caddyfile

@@ -0,0 +1,13 @@
+# DSA Tutoring microsite
+#
+# For local use, serves on port 8080
+# Replace :80 with your domain (e.g. dsa-tutoring.example.com) for
+# automatic HTTPS via Let's Encrypt.
+#
+# Run `python build.py` first to generate the public/ directory.
+
+:8080 {
+    root * /srv/public
+    encode gzip
+    file_server
+}

build.py

@@ -0,0 +1,287 @@
+#!/usr/bin/env python3
+"""Build script: scans shared/, generates zip downloads and public/index.html."""
+
+import html
+import os
+import shutil
+import zipfile
+from dataclasses import dataclass, field
+from pathlib import Path
+
+SHARED_DIR = Path("shared")
+PUBLIC_DIR = Path("public")
+ZIPS_DIR = PUBLIC_DIR / "zips"
+
+EXCLUDE_NAMES = {".DS_Store", "__pycache__", ".git", "Thumbs.db"}
+EXCLUDE_SUFFIXES = {".pyc"}
+
+
+@dataclass
+class SubSection:
+    name: str
+    zip_url: str
+    files: list[str]
+
+
+@dataclass
+class Section:
+    title: str
+    subsections: list[SubSection] = field(default_factory=list)
+    zip_url: str | None = None
+    files: list[str] | None = None
+
+
+# --- File filtering ---
+
+def should_include(path: Path) -> bool:
+    return path.name not in EXCLUDE_NAMES and path.suffix not in EXCLUDE_SUFFIXES
+
+
+# --- Zip and file listing ---
+
+def create_zip(source_dir: Path, zip_path: Path) -> None:
+    """Zip source_dir into zip_path; contents extract under a named folder."""
+    with zipfile.ZipFile(zip_path, "w", zipfile.ZIP_DEFLATED) as zf:
+        for file_path in sorted(source_dir.rglob("*")):
+            if not file_path.is_file():
+                continue
+            relative = file_path.relative_to(source_dir.parent)
+            if any(part in EXCLUDE_NAMES for part in relative.parts):
+                continue
+            if not should_include(file_path):
+                continue
+            zf.write(file_path, arcname=relative)
+
+
+def list_files(source_dir: Path) -> list[str]:
+    """Return sorted list of filtered relative file paths for display."""
+    results = []
+    for file_path in sorted(source_dir.rglob("*")):
+        if not file_path.is_file():
+            continue
+        relative = file_path.relative_to(source_dir)
+        if any(part in EXCLUDE_NAMES for part in relative.parts):
+            continue
+        if not should_include(file_path):
+            continue
+        results.append(str(relative))
+    return results
+
+
+# --- Data model construction ---
+
+def scan_shared() -> list[Section]:
+    sections = []
+
+    assignments_dir = SHARED_DIR / "assignments"
+    if assignments_dir.exists():
+        subdirs = sorted(
+            d for d in assignments_dir.iterdir()
+            if d.is_dir() and should_include(d)
+        )
+        if subdirs:
+            subsections = []
+            for subdir in subdirs:
+                zip_name = f"assignments-{subdir.name}.zip"
+                create_zip(subdir, ZIPS_DIR / zip_name)
+                subsections.append(SubSection(
+                    name=subdir.name,
+                    zip_url=f"zips/{zip_name}",
+                    files=list_files(subdir),
+                ))
+            sections.append(Section(title="Assignments", subsections=subsections))
+        else:
+            zip_name = "assignments.zip"
+            create_zip(assignments_dir, ZIPS_DIR / zip_name)
+            sections.append(Section(
+                title="Assignments",
+                zip_url=f"zips/{zip_name}",
+                files=list_files(assignments_dir),
+            ))
+
+    notes_dir = SHARED_DIR / "notes-and-examples"
+    if notes_dir.exists():
+        date_dirs = sorted(
+            d for d in notes_dir.iterdir()
+            if d.is_dir() and should_include(d)
+        )
+        subsections = []
+        for date_dir in date_dirs:
+            zip_name = f"notes-and-examples-{date_dir.name}.zip"
+            create_zip(date_dir, ZIPS_DIR / zip_name)
+            subsections.append(SubSection(
+                name=date_dir.name,
+                zip_url=f"zips/{zip_name}",
+                files=list_files(date_dir),
+            ))
+        sections.append(Section(title="Notes and Examples", subsections=subsections))
+
+    return sections
+
+
+# --- HTML rendering ---
+
+HTML_TEMPLATE = """\
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>DSA Tutoring</title>
+    <style>
+        *, *::before, *::after {{ box-sizing: border-box; }}
+        body {{
+            font-family: system-ui, sans-serif;
+            max-width: 800px;
+            margin: 0 auto;
+            padding: 2rem 1rem;
+            color: #1a1a1a;
+            background: #f5f5f5;
+        }}
+        h1 {{ font-size: 1.75rem; margin-bottom: 0.25rem; }}
+        .subtitle {{ color: #666; margin-bottom: 2rem; font-size: 0.95rem; }}
+        .section {{
+            background: white;
+            border: 1px solid #e0e0e0;
+            border-radius: 8px;
+            padding: 1.5rem;
+            margin-bottom: 1.5rem;
+        }}
+        .section > h2 {{
+            margin: 0 0 1rem 0;
+            font-size: 1.2rem;
+            padding-bottom: 0.75rem;
+            border-bottom: 1px solid #eee;
+        }}
+        .section-flat {{
+            display: flex;
+            flex-direction: column;
+            gap: 0.75rem;
+        }}
+        .subsection {{
+            padding-top: 0.75rem;
+            border-top: 1px solid #f0f0f0;
+        }}
+        .subsection:first-child {{ border-top: none; padding-top: 0; }}
+        .subsection-header {{
+            display: flex;
+            align-items: center;
+            justify-content: space-between;
+            flex-wrap: wrap;
+            gap: 0.5rem;
+            margin-bottom: 0.5rem;
+        }}
+        .subsection-header h3 {{
+            margin: 0;
+            font-size: 0.95rem;
+            font-family: monospace;
+            color: #333;
+        }}
+        .download-btn {{
+            display: inline-block;
+            padding: 0.35rem 0.85rem;
+            background: #2563eb;
+            color: white;
+            text-decoration: none;
+            border-radius: 5px;
+            font-size: 0.8rem;
+            white-space: nowrap;
+        }}
+        .download-btn:hover {{ background: #1d4ed8; }}
+        .file-list {{
+            list-style: none;
+            padding: 0;
+            margin: 0;
+        }}
+        .file-list li {{
+            font-family: monospace;
+            font-size: 0.82rem;
+            color: #555;
+            padding: 0.15rem 0;
+        }}
+        .file-list li::before {{ content: "— "; color: #bbb; }}
+    </style>
+</head>
+<body>
+    <h1>DSA Tutoring</h1>
+    <p class="subtitle">Lesson files and assignments. Click a download button to get a .zip archive.</p>
+{body}
+</body>
+</html>"""
+
+
+def render_file_list(files: list[str]) -> str:
+    items = "".join(f"        <li>{html.escape(f)}</li>\n" for f in files)
+    return f"      <ul class=\"file-list\">\n{items}      </ul>"
+
+
+def render_download_btn(zip_url: str, label: str) -> str:
+    return (
+        f"<a class=\"download-btn\" href=\"{html.escape(zip_url)}\" download>"
+        f"Download {html.escape(label)} (.zip)</a>"
+    )
+
+
+def render_section(section: Section) -> str:
+    if section.subsections:
+        parts = []
+        for sub in section.subsections:
+            parts.append(
+                f"    <div class=\"subsection\">\n"
+                f"      <div class=\"subsection-header\">\n"
+                f"        <h3>{html.escape(sub.name)}</h3>\n"
+                f"        {render_download_btn(sub.zip_url, sub.name)}\n"
+                f"      </div>\n"
+                f"{render_file_list(sub.files)}\n"
+                f"    </div>"
+            )
+        inner = "\n".join(parts)
+    else:
+        inner = (
+            f"    <div class=\"section-flat\">\n"
+            f"      {render_download_btn(section.zip_url, section.title)}\n"
+            f"{render_file_list(section.files or [])}\n"
+            f"    </div>"
+        )
+
+    return (
+        f"  <section class=\"section\">\n"
+        f"    <h2>{html.escape(section.title)}</h2>\n"
+        f"{inner}\n"
+        f"  </section>"
+    )
+
+
+def render_html(sections: list[Section]) -> str:
+    body = "\n".join(render_section(s) for s in sections)
+    return HTML_TEMPLATE.format(body=body)
+
+
+# --- Entry point ---
+
+def main() -> None:
+    os.chdir(Path(__file__).parent)
+
+    if PUBLIC_DIR.exists():
+        shutil.rmtree(PUBLIC_DIR)
+    PUBLIC_DIR.mkdir()
+    ZIPS_DIR.mkdir()
+
+    sections = scan_shared()
+    html_content = render_html(sections)
+
+    output = PUBLIC_DIR / "index.html"
+    output.write_text(html_content, encoding="utf-8")
+    print(f"Built {output}")
+
+    robots = PUBLIC_DIR / "robots.txt"
+    robots.write_text("User-agent: *\nDisallow: /\n", encoding="utf-8")
+    print(f"Built {robots}")
+
+    print(f"Zips in {ZIPS_DIR}:")
+    for z in sorted(ZIPS_DIR.iterdir()):
+        print(f"  {z.name}")
+
+
+if __name__ == "__main__":
+    main()

config/tailscale-serve-config.json

@@ -1,20 +0,0 @@
-{
-  "TCP": {
-    "443": {
-      "HTTPS": true
-    }
-  },
-  "Web": {
-    "static.tail8f43b.ts.net:443": {
-      "Handlers": {
-        "/": {
-          "Path": "/shared"
-        }
-      }
-    }
-  },
-  "AllowFunnel": {
-    "static.tail8f43b.ts.net:443": true
-  }
-}
-

docker-compose.yml

@@ -1,22 +1,24 @@
 services:
-  tailscale:
-    image: tailscale/tailscale:stable
-    container_name: tailscale-static
-    hostname: static
-    environment:
-      - TS_AUTHKEY=${TS_AUTHKEY}
-      - TS_STATE_DIR=/var/lib/tailscale
-      - TS_SERVE_CONFIG=/config/tailscale-serve-config.json
+  builder:
+    image: python:3-alpine
+    command: python /app/build.py
     volumes:
-      - tailscale-static-state:/var/lib/tailscale
-      - /dev/net/tun:/dev/net/tun   # shared interface across all Tailscale instances
-      - ./config:/config
-      - ./shared:/shared
-    cap_add:
-      - NET_ADMIN
-      - SYS_MODULE
+      - .:/app
+
+  caddy:
+    image: caddy:2-alpine
     restart: unless-stopped
-
+    depends_on:
+      builder:
+        condition: service_completed_successfully
+    ports:
+      - "8080:8080"
+    volumes:
+      - ./Caddyfile:/etc/caddy/Caddyfile
+      - ./public:/srv/public:ro
+      - caddy_data:/data
+      - caddy_config:/config
 
 volumes:
-  tailscale-static-state:
+  caddy_data:
+  caddy_config:

shared/README.md

@@ -1,4 +1,3 @@
-# Shared directory
-
-Files here are accessible to Tailscale under the `/shared` directory in the Docker container. To make a directory accessible to the public internet, configure `config/tailscale-serve-config` with the desired path-to-directory mapping.
+# Data structures tutoring
 
+Lesson files for data structures tutoring. Each date under `notes-and-examples` has a corresponding .zip file which can be downloaded to your computer.

shared/data-structures-tutoring/README.md

@@ -1 +0,0 @@
-Hello World!

shared/notes-and-examples/2026.01.21/main.py

@@ -0,0 +1,25 @@
+def bubble_sort_example():
+    numbers = [5, 24, 18, 95, 45, 502, 1]
+
+    for i in range(len(numbers)):
+        for j in range(i, len(numbers)):
+            if numbers[i] > numbers[j]:
+                numbers[j], numbers[i] = numbers[i], numbers[j]
+
+
+    print(numbers)
+
+def insertion_sort_example():
+    numbers = [5, 24, 18, 95, 502, 45, 1]
+
+    for i in range(1, len(numbers)):
+        for j in range(i - 1, -1, -1):
+            if numbers[j] > numbers[j + 1]:
+                numbers[j + 1], numbers[j] = numbers[j], numbers[j + 1]
+            else:
+                break
+
+    print(numbers)
+
+# bubble_sort_example();
+insertion_sort_example();

shared/notes-and-examples/2026.01.28/full_linked_list.py

@@ -0,0 +1,33 @@
+class Node:
+    next_node = None
+
+    def __init__(self, value):
+        self.value = value
+
+# Homework:
+# Make a linked list class with the functions:
+# - append(node): add a node to the end of the list
+# - insert(node, index): add a node to the middle of the list
+# - remove(index): remove the first matching node from the list
+
+class LinkedList:
+    head = None
+    tail = None
+
+    def append(self, thing):
+        if self.head==None:
+            self.head=Node(value=thing)
+            self.tail=self.head
+            return
+        self.tail.next_node=Node(value=thing)
+        self.tail=self.tail.next_node
+
+
+list1=LinkedList()
+list1.append('hi')
+list1.append('hi again')
+list1.append('why am I saying hi so many times?')
+print(list1.head.value)
+print(list1.head.next_node.value)
+print(list1.head.next_node.next_node.value)
+

shared/notes-and-examples/2026.01.28/main.py

@@ -0,0 +1,51 @@
+some_numbers = [2, 5, 20, 18, 4]
+
+more_numbers = some_numbers.copy()
+
+some_numbers[2] = 100
+
+# print(more_numbers[2])  # prints 100?
+
+class Sample:
+    other_samples = []
+    value = 0
+
+samples = [Sample(), Sample(), Sample()]
+more_samples = samples.copy()  # shallow copy
+samples[1].value = 10
+samples[1].other_samples.append(samples[0])
+# print(more_samples[1].value)  # 10
+
+samples.append(Sample())
+samples[3].value = 100
+# print(more_samples[3].value)
+
+other_sample.value = 40
+# print(sample.value)
+
+class Dog:
+    def __init__(self, age, name):
+        self.age = age
+        self.name = name
+
+# dog_1 = Dog()
+
+class Node:
+    next_node = None
+
+    def __init__(self, value):
+        self.value = value
+    
+node_1 = Node(0)
+node_2 = Node(0)
+
+node_2.value = 10
+
+node_1.next_node = node_2
+
+node_2.value = 20
+
+current_node = node_1
+while (current_node != None):
+    print(current_node.value)
+    current_node = current_node.next_node

shared/notes-and-examples/2026.01.28/object_reference_sample.py

@@ -0,0 +1,8 @@
+class Sample:
+    other_samples = []
+    value = 0
+
+sample = Sample()
+other_sample = sample
+sample.value = 20
+print(other_sample.value)

shared/notes-and-examples/2026.02.04/main.py

@@ -0,0 +1,13 @@
+class Node:
+    next = None
+    previous = None
+
+class Queue:
+    front = None
+    tail = None
+
+    def enqueue(self, node: Node):
+        pass
+
+    def dequeue(self):
+        pass

shared/notes-and-examples/2026.02.11/main.py

@@ -0,0 +1,23 @@
+class Node:
+    prev_node = None
+
+    def __init__(self, value) -> None:
+        self.value = value
+
+class Stack:
+    top: None | Node = None
+
+    def add(self, value):
+        pass
+    
+    def remove(self) -> None | Node:
+        pass
+    
+    def peek(self) -> None | Node:
+        pass
+    
+# Homework:
+# - Implement the other methods on the stack
+# - Implement linked list methods (see homework from 2026.01.28)
+# 
+# Submit to me by creating a .zip file and sending to: me@bchen.dev

shared/notes-and-examples/2026.02.28/homework.py

@@ -0,0 +1,2 @@
+# Homework:
+# See youtube-playlists under Assignments

shared/notes-and-examples/2026.02.28/linked_list_solution.py

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+# Solution to 2026.01.28 homework
+
+class Node:
+    prev_node: "Node | None" = None
+    next_node: "Node | None" = None
+
+    def __init__(self, value) -> None:
+        self.value = value
+
+class LinkedList:
+    head: "Node | None" = None
+    tail: "Node | None" = None
+
+    def append(self, thing):
+        if self.head==None:
+            self.head=Node(value=thing)
+            self.tail=self.head
+            return
+
+        if self.tail is not None:
+            self.tail.next_node=Node(value=thing)
+            if self.tail.next_node is not None:
+                self.tail.next_node.prev_node = self.tail
+            self.tail=self.tail.next_node
+
+    def prepend(self, thing):
+        previous_head = self.head
+        self.head = Node(value=thing)
+        self.head.next_node = previous_head
+
+        if previous_head is not None:
+            previous_head.prev_node = self.head
+
+    def insert(self, thing, index):
+        current_node = self.head
+        if current_node is None:
+            self.append(thing)
+            return
+
+        if index == 0:
+            self.prepend(thing)
+            return
+        
+        for _ in range(1, index):
+            if current_node is not None:
+                current_node = current_node.next_node
+        if current_node is None:
+            raise IndexError 
+
+        prev_next = current_node.next_node
+        current_node.next_node = Node(thing)
+        current_node.next_node.prev_node = current_node 
+        current_node.next_node.next_node = prev_next
+
+    
+    def print_list(self):
+        current_node = self.head
+        while current_node is not None:
+            print(current_node.value)
+            current_node = current_node.next_node
+
+example_list = LinkedList()
+example_list.append("first")
+example_list.append("second")
+example_list.append("fourth")
+example_list.insert("third", 2)
+example_list.insert("zero", 0)
+example_list.insert("last", 5)
+
+example_list.print_list()
+

shared/notes-and-examples/2026.02.28/queues.py

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+class Node:
+    next_node: "None | Node" = None
+    prev_node: "None | Node" = None
+
+    def __init__(self, value):
+        self.value = value
+
+class Queue:
+    front: "Node | None" = None
+    back: "Node | None" = None
+
+    def append(self, value):
+        if self.back is None:
+            self.front = Node(value)
+            self.back = self.front
+        else:
+            new_node = Node(value)
+            self.back.prev_node = new_node
+            new_node.next_node = self.back
+            self.back = new_node
+    
+    def popleft(self):
+        if self.front is not None:
+            prev_front = self.front
+
+            prev_node_in_queue = self.front.prev_node
+            self.front.next_node = None
+            self.front.prev_node = None
+            if prev_node_in_queue is not None:
+                prev_node_in_queue.next_node = None
+
+            self.front = prev_node_in_queue
+            
+            return prev_front
+        else:
+            return None
+
+    def print_queue(self):
+        current_node = self.front
+        while current_node is not None:
+            print(current_node.value)
+            current_node = current_node.prev_node
+
+
+queue = Queue()
+queue.append("first")
+queue.append("second")
+queue.append("third")
+queue.popleft()
+queue.popleft()
+queue.print_queue()