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Merge pull request #74 from lufftw/review/pattern-bitmask-dp
review(bitmask_dp): Assess Tier 2 - zero issues found
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‎docs/patterns/backtracking_exploration/templates.md‎

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## 2. Base Template: Permutations (LeetCode 46)
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> **Problem**: Given an array of distinct integers, return all possible permutations.

‎docs/patterns/math_number_theory/templates.md‎

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## 5. GCD of Array (LeetCode 1979)
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> **Problem**: Find GCD of all elements in array.
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## 8. Quick Reference Toolbox
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### 8.1 GCD / LCM
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## 9. Decision Guide
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### 9.1 Problem Signal → Tool Mapping

‎docs/patterns/prefix_sum/templates.md‎

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## 12. Template Quick Reference
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### 12.1 1. Basic Range Sum Query

‎docs/patterns/segment_tree_fenwick/templates.md‎

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## 8. Base Template: Range Sum Query - Mutable (LeetCode 307)
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> **Problem**: Given an integer array `nums`, handle multiple queries: (1) update element at index, (2) query sum of range [left, right].
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## 9. Variant: Count of Smaller Numbers After Self (LeetCode 315)
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> **Problem**: For each `nums[i]`, count how many `nums[j]` (j > i) are smaller than `nums[i]`.
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## 10. Advanced: Count of Range Sum (LeetCode 327)
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> **Problem**: Count subarrays where `lower <= sum(nums[i..j]) <= upper`.
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## 11. Pattern Comparison
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| Problem | Pattern | Data Structure | Key Technique |
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## 12. Decision Flowchart
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```
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## 13. Quick Reference Templates
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### 13.1 Fenwick Tree (Binary Indexed Tree)
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return total_count
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```
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‎docs/patterns/shortest_path/templates.md‎

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| Bellman-Ford (K iter) | O(K × E) | O(V) |
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| Minimax Dijkstra | O((V + E) log V) | O(V) |
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‎docs/patterns/topological_sort/templates.md‎

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| Cycle Detection | O(V + E) | O(V + E) |
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| Safe Nodes | O(V + E) | O(V) |
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‎docs/reviews/pattern-review-log.md‎

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| Pattern | Tier | Last Review | Issues (C/M/m/n) | Status |
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|---------|------|-------------|------------------|--------|
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| binary_search | Tier 2 | 2025-01-07 | 0/0/1/2 | Reviewed |
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| bitmask_dp | Pending | - | - | Queued |
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| bitmask_dp | Tier 2 | 2025-01-07 | 0/0/0/0 | Reviewed |
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| dp_1d_linear | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
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| dp_knapsack_subset | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
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| game_theory_dp | Pending | - | - | Queued |
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## Bitmask DP Review - 2025-01-07
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### Files Reviewed
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- `docs/patterns/bitmask_dp/templates.md` (827 lines)
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- `docs/patterns/bitmask_dp/intuition.md` (253 lines)
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### Reference Standards
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- Gold Standard: `sliding_window/templates.md`
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- Ontology Entry: `BitmaskDP` from `ontology/api_kernels.toml`
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### Findings
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**No issues found.** This is the first pattern reviewed with zero cosmetic issues.
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### Positive Observations (Not Issues)
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| Aspect | Assessment |
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|--------|------------|
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| **API Kernel Header** | ✅ `BitmaskDP` with clear "set states as integers" mechanism |
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| **Bit Manipulation Cheat Sheet** | ✅ Section 4 with all essential operations |
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| **Universal Template Structure** | ✅ Section 5 shows base pattern |
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| **Three Pattern Variants** | ✅ Subset Enum (LC 78), BFS+Bitmask (LC 847), Set Cover (LC 1125) |
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| **Embedded Problem Cards** | ✅ Full implementations with Key Insight, Template Mapping, Complexity |
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| **Problem Comparison** | ✅ Section 48 compares state, transition, output across problems |
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| **Pattern Evolution** | ✅ Section 49 shows progression from simple to complex |
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| **Decision Tree** | ✅ Section 53 with ASCII flowchart |
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| **Constraint Analysis** | ✅ Why n ≤ 20 explained clearly |
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| **Red Flags Section** | ✅ Section 55 explains when NOT to use bitmask DP |
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| **Bit Manipulation Utilities** | ✅ Section 59 with reusable helper functions |
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| **Intuition Quality** | ✅ "Binary Light Switches" mental model, hypercube visualization |
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| **Common Mistakes** | ✅ 4 pitfalls: wrong bit check, forgetting node in state, single-source BFS, dict mutation |
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### Summary
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| Category | Critical | Major | Minor | Nit | Total |
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|----------|----------|-------|-------|-----|-------|
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| Concept | 0 | 0 | 0 | 0 | 0 |
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| Explanation | 0 | 0 | 0 | 0 | 0 |
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| Engineering | 0 | 0 | 0 | 0 | 0 |
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| **Total** | 0 | 0 | 0 | 0 | **0** |
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### Tier Assessment
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- **Previous Tier**: Pending
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- **New Tier**: Tier 2 (Silver)
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- **Rationale**: First pattern with zero issues. Comprehensive bitmask DP coverage with excellent embedded problem cards. The three-pattern taxonomy (Subset Enum, BFS+Bitmask, Set Cover) is clearly differentiated. Strong constraint analysis explains the n ≤ 20 limit. The "Binary Light Switches" mental model in intuition.md is memorable. Document structure is unique (60 sections due to embedded problem metadata) but effective.
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### Action Items
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- [x] No fixes required - pattern meets quality standards
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---
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*Pattern Review Log - NeetCode Practice Framework*

‎tools/patterndocs/composer.py‎

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from .sections import generate_toc, add_section_numbers
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def _strip_separators(content: str) -> str:
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"""Remove leading and trailing '---' separators from content."""
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lines = content.split("\n")
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# Skip leading empty lines and separator
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while lines and (lines[0].strip() == "" or lines[0].strip() == "---"):
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lines.pop(0)
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# Skip trailing empty lines and separator
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while lines and (lines[-1].strip() == "" or lines[-1].strip() == "---"):
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return "\n".join(lines)
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def compose_document(
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"""Compose the final document from source files."""
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header_contents = [f.read_text(encoding="utf-8").strip() for f in header_files]
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problem_contents = [f.read_text(encoding="utf-8").strip() for f in problem_files]
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footer_contents = [f.read_text(encoding="utf-8").strip() for f in footer_files]
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# Read all content and strip separators to avoid duplicates
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header_contents = [_strip_separators(f.read_text(encoding="utf-8")) for f in header_files]
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problem_contents = [_strip_separators(f.read_text(encoding="utf-8")) for f in problem_files]
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footer_contents = [_strip_separators(f.read_text(encoding="utf-8")) for f in footer_files]
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# First pass: collect section info for TOC
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all_sections_info: list[tuple[int, str, str]] = []

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