Merge pull request #70 from lufftw/review/pattern-trie

review(trie): Pattern quality review - Tier 2 assessment

Author: lufftw

docs/patterns/trie/templates.md

@@ -105,8 +105,6 @@ def _find_node(self, prefix: str) -> Optional[TrieNode]:
 
 ---
 
----
-
 ## 6. Problem: Implement Trie (Prefix Tree) [LC 208] - BASE
 
 > **Pattern**: Basic Trie Operations
@@ -193,8 +191,6 @@ startsWith("ap") → True  (node exists)
 
 ---
 
----
-
 ## 7. Problem: Design Add and Search Words Data Structure [LC 211]
 
 > **Pattern**: Trie with Wildcard Search
@@ -307,8 +303,6 @@ search("b.d"):
 
 ---
 
----
-
 ## 8. Problem: Word Search II [LC 212]
 
 > **Pattern**: Trie + Backtracking
@@ -434,8 +428,6 @@ Result: ["oath", "eat"]
 
 ---
 
----
-
 ## 9. Problem: Replace Words [LC 648]
 
 > **Pattern**: Trie Prefix Replacement
@@ -558,8 +550,6 @@ Where D = dictionary size, W = words in sentence, L = word length.
 
 ---
 
----
-
 ## 10. Problem: Search Suggestions System [LC 1268]
 
 > **Pattern**: Trie Autocomplete
@@ -710,8 +700,6 @@ Query "mouse": ["mouse","mousepad"]
 
 ---
 
----
-
 ## 11. Pattern Comparison
 
 | Problem | Trie Modification | Search Type | Extra Data |
@@ -762,8 +750,6 @@ Need exact word lookup?
 
 ---
 
----
-
 ## 14. Decision Guide: When to Use Trie
 
 ### 14.1 Use Trie When
@@ -823,8 +809,6 @@ Do you need prefix operations?
 
 ---
 
----
-
 ## 15. Quick Reference Templates
 
 ### 15.1 Basic Trie Structure

docs/reviews/pattern-review-log.md

@@ -63,7 +63,7 @@ This log records all pattern review findings, decisions, and resolutions. Each r
 | topological_sort | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
 | tree | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
 | tree_dp | Pending | - | - | Queued |
-| trie | Pending | - | - | Queued |
+| trie | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
 | union_find | Tier 2 | 2025-01-07 | 0/0/1/0 | Reviewed |
 
 **Legend**: C=Critical, M=Major, m=Minor, n=Nit
@@ -731,4 +731,66 @@ END TEMPLATE
 
 ---
 
+## Trie Review - 2025-01-07
+
+### Files Reviewed
+- `docs/patterns/trie/templates.md` (979 lines)
+- `docs/patterns/trie/intuition.md` (304 lines)
+
+### Reference Standards
+- Gold Standard: `sliding_window/templates.md`
+- Ontology Entry: `TriePrefixSearch` from `ontology/api_kernels.toml`
+
+### Findings
+
+#### [TR-001]: Duplicate Section Separators
+
+| Field | Value |
+|-------|-------|
+| **Category** | Engineering |
+| **Severity** | Minor |
+| **Location** | `docs/patterns/trie/templates.md` (8 locations between sections 5-15) |
+| **Issue** | Double `---` separators appear between major sections, creating visual inconsistency. |
+| **Why It Matters** | Cosmetic issue affecting document consistency. Does not impact functionality. |
+| **Decision** | Fix |
+| **Resolution** | Removed duplicate separators (8 locations). |
+
+### Positive Observations (Not Issues)
+
+| Aspect | Assessment |
+|--------|------------|
+| **API Kernel** | ✅ `Trie` / `TriePrefixSearch` with tree-based prefix mechanism |
+| **When to Use Section** | ✅ Section 2 with signal table (prefix matching, autocomplete, wildcards) |
+| **Core Structure** | ✅ Section 3 with TrieNode class and optional enhancements |
+| **Base Operations** | ✅ Section 4 with Insert, Search, Prefix - all O(L) |
+| **Pattern Variations** | ✅ Section 5 summary table of 5 problem variants |
+| **Problem Coverage** | ✅ 5 problems: LC 208 (Base), 211 (Wildcard), 212 (Grid), 648 (Replace), 1268 (Autocomplete) |
+| **Code Templates Summary** | ✅ Section 15 with 6 templates including Autocomplete with Top-K |
+| **Decision Guide** | ✅ Multiple flowcharts in Sections 13-14 with Trie vs Alternatives |
+| **Trace Examples** | ✅ Comprehensive traces for all 5 problem variants |
+| **Why Trie is Optimal** | ✅ Comparison tables showing Trie O(L) vs Hash Set O(L²) for prefixes |
+| **Key Optimizations** | ✅ Store word at node, prune empty branches, in-place grid marking |
+| **Intuition Quality** | ✅ 5 mental models: Branching Path, Autocomplete Tree, Wildcard Branching, Grid+Trie, Shortest Prefix |
+| **Common Pitfalls** | ✅ 4 pitfalls: confusing prefix vs word, forgetting is_end, duplicates, not pruning |
+| **Practice Progression** | ✅ Level 1-4 problem sequence |
+
+### Summary
+
+| Category | Critical | Major | Minor | Nit | Total |
+|----------|----------|-------|-------|-----|-------|
+| Concept | 0 | 0 | 0 | 0 | 0 |
+| Explanation | 0 | 0 | 0 | 0 | 0 |
+| Engineering | 0 | 0 | 1 | 0 | 1 |
+| **Total** | 0 | 0 | 1 | 0 | **1** |
+
+### Tier Assessment
+- **Previous Tier**: Pending
+- **New Tier**: Tier 2 (Silver)
+- **Rationale**: Most comprehensive pattern documentation with 15 sections and 979 lines. Excellent coverage of 5 distinct Trie variants with clear delta-from-base explanations. The "Why Trie is Optimal" comparison tables are particularly valuable. Strong intuition.md with 5 mental models and decision flowchart. Minor cosmetic issue with duplicate separators (8 locations).
+
+### Action Items
+- [x] Fix duplicate section separators (8 locations)
+
+---
+
 *Pattern Review Log - NeetCode Practice Framework*