Complete DP-1

[satish-paraddi]

No description provided.

[super30admin]

Coin Change (Problem-1.py)

Excellent work! Your solution is actually superior to the reference solution in multiple ways:

1. Better Algorithm Choice: You chose bottom-up DP over the recursive approach, which avoids the exponential time complexity of the reference solution.

2. Optimal Complexity: Your O(m*n) time and O(m) space complexity is the standard optimal solution for this problem.

3. Clean Implementation: The code is well-organized with helpful comments explaining the DP state.

4. Edge Case Handling: You correctly handle the amount == 0 case and the impossible case (returning -1).

Minor suggestions for improvement:

• The early return if amount == 0: return 0 is redundant since dp[0] = 0 already handles this case, but it doesn't hurt readability.
• You could add a brief comment explaining why dp[i-c]+1 works (adding one more coin to the optimal solution for amount i-c).
• Consider using math.inf instead of float("inf") for slightly better readability, though this is purely stylistic.

Overall, this is a textbook-quality solution that demonstrates strong understanding of dynamic programming.

VERDICT: PASS

---

House Robber (Problem-2.py)

Excellent work! Your solution demonstrates a strong understanding of dynamic programming. Here are some observations:

Strengths:

1. Your iterative DP approach is much more efficient than the reference's naive recursion
2. You correctly handled edge cases (empty array, single house)
3. The code is clean, well-commented, and easy to follow
4. The recurrence relation is correctly implemented

Areas for improvement:

1. Space Optimization: You can reduce space complexity from O(n) to O(1) by using just two variables to track the previous two states:

   def rob(self, nums: List[int]) -> int:
       if not nums:
           return 0
       prev1, prev2 = 0, 0
       for num in nums:
           temp = prev1
           prev1 = max(prev1, prev2 + num)
           prev2 = temp
       return prev1

2. Type Hinting: Consider adding type hints for the parameter (though nums: List[int] is already there)

Overall, this is a solid solution that correctly solves the problem with optimal time complexity.

VERDICT: PASS