feat: add searchable GitHub Pages site for solutions

.github/scripts/generate-index.py

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+#!/usr/bin/env python3
+"""Generate the searchable GitHub Pages index from solution headers."""
+
+import json
+import re
+from pathlib import Path
+
+LANGUAGE_EXTENSIONS = {
+    "python": {".py"},
+    "javascript": {".js"},
+    "cpp": {".cpp", ".cc", ".cxx"},
+    "java": {".java"},
+    "typescript": {".ts", ".tsx"},
+}
+
+TOPIC_RULES = [
+    ("Dynamic Programming", r"\b(dynamic programming|unique paths|minimum path|coin change|fibonacci|climbing stairs|longest increasing subsequence|wildcard matching|maximum subarray|kadane)\b"),
+    ("Graphs", r"\b(graph|islands|word ladder|shortest path|escape path|flood fill|connected component|course schedule)\b"),
+    ("Trees", r"\b(tree|bst|binary search tree|n-ary)\b"),
+    ("Linked Lists", r"\b(linked list|rotate list|add two numbers|merge two sorted lists|remove duplicates from sorted list)\b"),
+    ("Stack & Queue", r"\b(parentheses|braces|brackets|backspace|next greater element|queue|stack|parking system)\b"),
+    ("Backtracking", r"\b(n-queens|permutation|permutations|subsets|combinations|combination sum|generate parentheses)\b"),
+    ("Sliding Window", r"\b(longest substring|minimum window|subarray|sliding window|consecutive)\b"),
+    ("Two Pointers", r"\b(3sum|4sum|two sum|pair with given|palindrome|merge intervals|backspaces in string)\b"),
+    ("Matrix", r"\b(matrix|spiral|row with|max 1s|diagonal|rotate 90|flood fill)\b"),
+    ("Sorting", r"\b(sort|sorting|rank|median|kth largest|relative ranks|height checker|frequency sorting)\b"),
+    ("Searching", r"\b(search|missing number|missing element|find the difference|peak element|pivot index|nearest value)\b"),
+    ("Hash Table", r"\b(two sum|frequency|counter|anagram|duplicate|intersection|common characters|common elements|good pairs|word order|most frequent)\b"),
+    ("Strings", r"\b(string|word|sentence|character|vowel|consonant|camelcase|morse|regex|encryption|decode|encode|prefix|suffix|text|ip validation|phone number|credit card)\b"),
+    ("Arrays", r"\b(array|subarray|elements|indices|index|triplets|pairs|partition|running sum|rotate array|jump game|candies|missing)\b"),
+    ("Math", r"\b(number|digit|prime|factorial|gcd|multiple|sum|power|square root|binary to decimal|roman numeral|fibonacci|bits|xor|bitwise|area|duration|time delta|leap year)\b"),
+    ("Greedy", r"\b(jump game|minimum operations|largest number|maximum number|assign|distribute|water bottles|hurdle|buy and sell|best time)\b"),
+    ("Bit Manipulation", r"\b(bit|binary|xor|complement|set bits|ones|flips)\b"),
+    ("Simulation", r"\b(simulator|simulate|design parking|calendar|tic-tac-toe|bouncing balls|counting valleys|fizzbuzz|game|solar system)\b"),
+]
+
+def extract_header_info(filepath):
+    problem = None
+    source = None
+    topics = []
+    with filepath.open("r", encoding="utf-8", errors="ignore") as file:
+        for line in list(file)[:15]:
+            match = re.match(r"^\s*(?:#|//|/\*+|\*|<!--)\s*(Problem|Source|Topics?)\s*:\s*(.*?)\s*(?:\*/|-->)?\s*$", line, re.IGNORECASE)
+            if not match:
+                continue
+            key, value = match.group(1).lower(), match.group(2).strip()
+            if key == "problem":
+                problem = value
+            elif key == "source":
+                source = value
+            else:
+                topics.extend(item.strip() for item in re.split(r"[,;|]", value) if item.strip())
+    return problem, source, topics
+
+def infer_topics(problem):
+    normalized = problem.lower()
+    matches = [topic for topic, pattern in TOPIC_RULES if re.search(pattern, normalized)]
+    return matches or ["General"]
+
+def generate_index():
+    repo_root = Path(__file__).resolve().parents[2]
+    solutions_dir = repo_root / "solutions"
+    output_path = repo_root / "docs" / "data.json"
+    solutions = []
+
+    for language, extensions in LANGUAGE_EXTENSIONS.items():
+        language_dir = solutions_dir / language
+        if not language_dir.is_dir():
+            continue
+        for filepath in sorted(language_dir.iterdir()):
+            if not filepath.is_file() or filepath.suffix.lower() not in extensions:
+                continue
+            problem, source, topics = extract_header_info(filepath)
+            problem = problem or filepath.stem
+            solutions.append({
+                "name": filepath.stem,
+                "language": language,
+                "filename": filepath.name,
+                "problem": problem,
+                "source": source or "",
+                "topics": topics or infer_topics(problem),
+                "path": filepath.relative_to(repo_root).as_posix(),
+            })
+
+    output_path.parent.mkdir(parents=True, exist_ok=True)
+    output_path.write_text(json.dumps(solutions, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
+    counts = {language: sum(item["language"] == language for item in solutions) for language in LANGUAGE_EXTENSIONS}
+    print(f"Generated {len(solutions)} solutions in {output_path}")
+    for language, count in counts.items():
+        if count:
+            print(f"  {language}: {count}")
+
+if __name__ == "__main__":
+    generate_index()

.github/workflows/update-index.yml

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+name: Update Solutions Index
+
+on:
+  push:
+    branches:
+      - main
+    paths:
+      - 'solutions/**'
+      - '.github/scripts/generate-index.py'
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  update-index:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: true
+
+      - name: Generate solutions index
+        run: python3 .github/scripts/generate-index.py
+
+      - name: Commit and push if changed
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+          if git diff --quiet -- docs/data.json; then
+            echo "No changes to index"
+          else
+            git add docs/data.json
+            git commit -m "chore: update solutions index [skip ci]"
+            git push
+          fi

docs/README.md

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+# Algorithm Solutions - GitHub Pages
+
+A searchable, filterable web interface for browsing algorithm solutions by language, topic, and problem.
+
+## Features
+
+- Search by problem name or file name
+- Filter by programming language and algorithm topic
+- Direct links to problem sources and solution files
+- Responsive layout and system dark-mode support
+- No build step required for GitHub Pages
+
+## How to Update the Solution Index
+
+The index is generated from solution file headers and problem names.
+
+### Automatic Method
+
+The GitHub Actions workflow regenerates `docs/data.json` when files under `solutions/` change on `main`. It has explicit permission to commit the generated index.
+
+### Manual Method
+
+From the repository root, run the PowerShell wrapper:
+
+```powershell
+powershell -ExecutionPolicy Bypass -File .\generate-index.ps1
+```
+
+On Linux or macOS, run the Python generator:
+
+```bash
+python3 .github/scripts/generate-index.py
+```
+
+Both commands use the same generator, so the generated index stays consistent across platforms.
+
+## Topic Metadata
+
+Add an optional `Topics` header to a solution to override automatic topic detection. Separate multiple topics with commas.
+
+Python example:
+
+```python
+# Problem: Two Sum
+# Source: https://leetcode.com/problems/two-sum/
+# Topics: Arrays, Hash Table, Two Pointers
+```
+
+JavaScript/C++/Java example:
+
+```javascript
+// Problem: Valid Parentheses
+// Source: https://leetcode.com/problems/valid-parentheses/
+// Topics: Strings, Stack & Queue
+```
+
+When no `Topics` header is present, the generator assigns topics using the problem title. Unmatched titles are placed in **General** and can be given more specific topics through the header.
+
+## File Structure
+
+```
+docs/
+├── index.html
+├── style.css
+├── script.js
+├── data.json
+└── README.md
+```
+
+Each solution card shows its problem name, language, topics, source link (when available), and repository file link.
+
+**Site URL:** https://aaqibhafeezkhan.github.io/algo-solutions-python/