DP-2 complete

[KartavyaBhatt]

No description provided.

[super30admin]

Paint House (Problem1.py)

Strengths:

• Good understanding of the DP approach for this classic problem
• Efficient O(n) time complexity vs reference's O(2^n)
• O(1) space complexity is optimal
• Clean iteration-based approach without recursion overhead

Areas for Improvement:

• Critical bug: Return min(dp) not max(dp) - this fundamentally breaks the solution
• Fix type hint from List[int][int] to List[List[int]]
• Add import math for math.inf
• Consider renaming method to minCost for consistency with problem expectations
• Add comments explaining the DP logic for clarity

VERDICT: NEEDS_IMPROVEMENT

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Coin Change II (Problem2.py)

Strengths:

1. Excellent explanation in comments showing clear understanding of the problem and why DP is needed
2. Correctly implements the 2D DP concept in a space-optimized 1D array
3. Clean, readable code with good variable naming
4. Properly handles the base case (dp[0] = 1)
5. The solution is more efficient than the reference solution (O(amount × len(coins)) vs O(2^n))

Areas for Improvement:

1. The comment mentions "Time complexity: O(amount * len(coins))" but then says "Space complexity: O(amount * len(coins))" which is incorrect - space is O(amount) for the 1D DP approach
2. Could add type hints for better code documentation (e.g., def change(self, amount: int, coins: List[int]) -> int: is already present, which is good)
3. The solution could benefit from a brief comment explaining the DP transition formula

VERDICT: PASS