nit

backend/data/questions/add-test-cases-prompt.md

@@ -0,0 +1,222 @@
+# Add Test Cases to Question Files - Context Prompt
+
+## Overview
+
+This document provides context for adding `function_signature` and `test_cases` sections to question YAML files in the CodeTutor project.
+
+## Current Status
+
+- **Total question files**: 401
+- **Files with test cases**: 120
+- **Files needing test cases**: ~281
+
+## File Location
+
+All question files are in: `/mnt/work/dev/portfolio/codetutor/backend/data/questions/`
+
+## YAML Structure
+
+Each question file should have `function_signature` and `test_cases` sections placed **after the `patterns` section and before the `description` section**.
+
+### Example Structure
+
+```yaml
+title: Two Sum
+slug: two-sum
+difficulty: easy
+leetcode_id: 1
+leetcode_url: https://leetcode.com/problems/two-sum/
+categories:
+  - arrays
+  - hash-tables
+patterns:
+  - two-pointers
+
+function_signature: "def two_sum(nums: list[int], target: int) -> list[int]:"
+
+test_cases:
+  visible:
+    - input: { nums: [2, 7, 11, 15], target: 9 }
+      expected: [0, 1]
+    - input: { nums: [3, 2, 4], target: 6 }
+      expected: [1, 2]
+    - input: { nums: [3, 3], target: 6 }
+      expected: [0, 1]
+  hidden:
+    - input: { nums: [1, 5, 3, 7, 2], target: 10 }
+      expected: [2, 3]
+    - input: { nums: [-1, -2, -3, -4, -5], target: -8 }
+      expected: [2, 4]
+    - input: { nums: [0, 4, 3, 0], target: 0 }
+      expected: [0, 3]
+
+description: |
+  Given an array of integers...
+```
+
+## Function Signature Conventions
+
+- Use Python type hints: `list[int]`, `str`, `int`, `bool`, `list[list[int]]`
+- Use snake_case for function and parameter names
+- Match LeetCode's function signature where possible, but use Pythonic naming:
+  - `twoSum` → `two_sum`
+  - `numCourses` → `num_courses`
+  - `obstacleGrid` → `obstacle_grid`
+
+### Special Types
+
+For linked lists and trees, use:
+- `ListNode` for linked list problems
+- `TreeNode` for binary tree problems
+
+Example:
+```yaml
+function_signature: "def reorder_list(head: ListNode) -> None:"
+function_signature: "def diameter_of_binary_tree(root: TreeNode) -> int:"
+```
+
+## Test Case Guidelines
+
+### Visible Tests (2-3 cases)
+- Include the examples from the problem description
+- Cover basic happy path scenarios
+- Keep inputs simple and easy to understand
+
+### Hidden Tests (5-7 cases)
+- **Edge cases**: empty inputs, single elements, nulls
+- **Boundary conditions**: min/max values, overflow scenarios
+- **Special patterns**: all same values, strictly increasing/decreasing
+- **Negative numbers**: if applicable
+- **Large inputs**: for performance edge cases
+
+### Data Types in YAML
+
+```yaml
+# Arrays
+input: { nums: [1, 2, 3] }
+
+# Strings (use quotes)
+input: { s: "hello" }
+
+# Nested arrays (matrices)
+input: { grid: [[0, 0, 0], [0, 1, 0], [0, 0, 0]] }
+
+# Multiple parameters
+input: { nums: [1, 2, 3], target: 6 }
+
+# Boolean expected values
+expected: true
+expected: false
+
+# Linked lists (as arrays)
+input: { head: [1, 2, 3, 4] }
+expected: [1, 4, 2, 3]
+
+# Trees (level-order with nulls)
+input: { root: [1, 2, 3, null, 4] }
+```
+
+## Finding Files Without Test Cases
+
+Run this command to find files missing the `function_signature`:
+
+```bash
+cd /mnt/work/dev/portfolio/codetutor/backend/data/questions
+for f in *.yaml; do
+  if ! grep -q "^function_signature:" "$f"; then
+    echo "$f"
+  fi
+done
+```
+
+Or use grep to count:
+```bash
+grep -L "^function_signature:" *.yaml | wc -l
+```
+
+## Workflow
+
+1. **Read the problem file** to understand:
+   - The function parameters and return type
+   - Example inputs/outputs from the `examples` section
+   - Constraints for edge case ideas
+
+2. **Add the sections** after `patterns:` and before `description:`
+
+3. **Verify YAML syntax** - ensure proper indentation (2 spaces)
+
+4. **Commit in batches** with message format:
+   ```
+   feat(content): add test cases for N additional problems
+   ```
+
+## Priority Problems
+
+Focus on commonly asked interview problems first:
+- LeetCode Top 100
+- Blind 75
+- NeetCode 150
+
+### Categories Still Needing Coverage
+
+Run this to see which files still need test cases:
+```bash
+grep -L "^function_signature:" *.yaml | head -50
+```
+
+## Example: Adding Tests to a New File
+
+### Before (file without tests):
+```yaml
+patterns:
+  - sliding-window
+
+description: |
+  ...
+```
+
+### After (file with tests):
+```yaml
+patterns:
+  - sliding-window
+
+function_signature: "def max_sliding_window(nums: list[int], k: int) -> list[int]:"
+
+test_cases:
+  visible:
+    - input: { nums: [1, 3, -1, -3, 5, 3, 6, 7], k: 3 }
+      expected: [3, 3, 5, 5, 6, 7]
+    - input: { nums: [1], k: 1 }
+      expected: [1]
+  hidden:
+    - input: { nums: [9, 11], k: 2 }
+      expected: [11]
+    - input: { nums: [4, 3, 2, 1], k: 2 }
+      expected: [4, 3, 2]
+    - input: { nums: [7, 7, 7, 7], k: 3 }
+      expected: [7, 7]
+
+description: |
+  ...
+```
+
+## Changelog Update
+
+After committing, update `/mnt/work/dev/portfolio/codetutor/changelog.md`:
+
+```markdown
+## [Unreleased]
+
+### Added
+
+- Test cases for N additional questions bringing total to M:
+  - Category: problem1, problem2, problem3
+  - Category: problem4, problem5
+```
+
+## Notes
+
+- The test runner uses Pyodide (Python in WebAssembly) to execute code
+- Visible tests run client-side; hidden tests are validated server-side
+- Expected outputs must be JSON-serializable
+- Order matters for list outputs unless the problem states "any order"