Merge Diff ARC-AGI Task

Overview

This skill addresses tasks that combine git branch merging with ARC-AGI pattern recognition challenges. These tasks typically involve:

1. Extracting and merging multiple git branches from bundles
2. Resolving merge conflicts between different algorithm implementations
3. Analyzing input/output grid examples to discover transformation patterns
4. Implementing a

   map

   function that generalizes to hidden test cases

Pre-flight Checklist

Before starting any git operations, complete these setup steps to avoid interruptions:

1. Configure git identity (prevents merge commit failures):

   git config user.email "agent@example.com"
   git config user.name "Agent"
   

2. Verify working directory is clean or stash changes

3. Identify the base branch to work from

Phase 1: Git Operations

Branch Extraction and Setup

1. Extract branches from bundle files:

   git bundle unbundle <bundle-file>
   

2. Create local branches from the extracted refs:

   git checkout -b <branch-name> <ref>
   

3. Before merging, examine each branch's implementation:

   • Read the algorithm files on each branch
   • Understand what approach each implementation takes
   • Note dependencies (numpy, etc.) and coding styles

Merge Conflict Resolution

When merge conflicts occur:

1. Do not blindly choose one side - both implementations may contain insights
2. Understand both approaches before resolving:
   • What pattern does each implementation detect?
   • What edge cases does each handle?
   • Can elements from both be combined?
3. Document the resolution rationale - explain why the final implementation was chosen

Phase 2: Pattern Analysis Framework

Systematic Analysis Process

Apply this structured approach to avoid jumping between hypotheses:

1. Inventory the data:

   • Grid dimensions for each example
   • Unique values present (zero vs non-zero)
   • Positions of each unique value

2. Compare input to output:

   • What values appear in output that weren't in input?
   • What spatial relationships change?
   • What remains constant?

3. Formulate a single hypothesis and test against ALL examples before moving on

4. Document findings in a structured format:

   Example N:
   - Input: [dimensions, unique values, positions]
   - Output: [dimensions, patterns observed]
   - Hypothesis test: [pass/fail with explanation]
   

Common ARC-AGI Patterns to Consider

• Tiling patterns: Values repeated across grid based on position formulas
• Diagonal patterns: Relationships based on

  i+j

  ,

  i-j

  , or similar
• First occurrence mapping: Order determined by where values first appear
• Modular arithmetic:

  (i+j) % n

  or similar cyclic patterns
• Spatial transformations: Rotations, reflections, translations

Pattern Verification Checklist

Before finalizing an algorithm:

• Does the pattern explain ALL provided examples?
• Is the formula derivation logically justified (not just empirically fitted)?
• What happens with edge cases:
  • Empty grids or all-zero grids?
  • Single unique non-zero value?
  • Collision scenarios (e.g., two values with same modular position)?
• Would the pattern generalize to different grid sizes?

Phase 3: Implementation

Algorithm Development

1. Start with clear documentation:

   def map(grid: list[list[int]]) -> list[list[int]]:
       """
       Transform input grid to output grid.
   
       Algorithm:
       1. [Step 1 explanation]
       2. [Step 2 explanation]
   
       Edge cases handled:
       - [Case 1]
       - [Case 2]
       """
   

2. Handle edge cases explicitly:

   if not grid or not grid[0]:
       return grid
   unique_values = [v for v in set(flatten(grid)) if v != 0]
   if len(unique_values) == 0:
       return [[0] * len(grid[0]) for _ in range(len(grid))]
   

3. Avoid collision bugs: When mapping values to positions based on formulas, verify that no two values map to the same position, or handle the collision explicitly

Testing Strategy

Create a reusable test function early:

def test_map_function(examples_path: str) -> bool:
    """Test map function against all examples."""
    import json
    with open(examples_path) as f:
        examples = json.load(f)

    all_passed = True
    for i, ex in enumerate(examples):
        result = map(ex['input'])
        expected = ex['output']
        if result != expected:
            print(f"Example {i} FAILED")
            print(f"  Expected: {expected}")
            print(f"  Got: {result}")
            all_passed = False
        else:
            print(f"Example {i} PASSED")
    return all_passed

Run this after every algorithm change rather than writing ad-hoc test scripts.

Phase 4: Verification

Final Verification Checklist

Before declaring the task complete:

1. All examples pass: Run test function against examples.json
2. Algorithm is documented: Comments explain the "why" not just the "what"
3. Edge cases are handled: Empty inputs, single values, boundary conditions
4. Generalization is justified: The algorithm logic follows from the pattern, not from fitting to specific examples
5. Git state is clean: Merge is complete, no uncommitted changes

Generalization Confidence Assessment

Rate confidence that the solution will pass hidden tests:

• High confidence: Pattern logic is clearly derived from first principles; edge cases explicitly handled; formula is mathematically justified
• Medium confidence: Pattern works on all examples but some aspects were discovered empirically
• Low confidence: Solution was fitted to examples without clear logical derivation

If confidence is medium or low, revisit the pattern analysis phase.

Common Pitfalls

Pitfall	Prevention
Git config not set before merge	Run git config commands at start
Jumping between hypotheses	Test each hypothesis against ALL examples before abandoning
Ignoring one branch's implementation	Read and understand both implementations first
No edge case handling	Explicitly list and handle edge cases in code
Empirical fitting without justification	Document why the formula works, not just that it works
Testing with ad-hoc scripts	Create reusable test function early
Missing collision handling	Verify no two values map to same position

Resources

references/

The

references/

directory contains detailed guidance:

• pattern_analysis_template.md

  - Structured template for documenting pattern analysis

• git_merge_checklist.md

  - Step-by-step git operations checklist