DP-1

[sumanth00100]

No description provided.

[super30admin]

The Coin Change (problem1.java)

Your solution is well-implemented and correct for the given problem. Here are some points to consider for improvement:

1. Instead of using 999999 to represent infinity, it's better to use a constant like Integer.MAX_VALUE or a value that is guaranteed to be larger than the maximum possible number of coins (which is at most 10,000 given the constraints). However, be cautious with Integer.MAX_VALUE to avoid integer overflow when adding 1. Alternatively, you can use amount + 1 as an upper bound since the maximum coins needed cannot exceed the amount (if using coin 1).
2. The space complexity can be optimized to O(n) by using a 1D array for the DP table, since each row only depends on the previous row and the current row.
3. The code comments are good, but you could add more comments to explain the DP recurrence for better clarity.
4. Consider adding an edge case for when amount is 0 at the beginning to return 0 immediately, though your current solution handles it correctly.

Overall, your solution is efficient and follows best practices. With minor adjustments, it can be made more robust.

VERDICT: PASS

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House Robber (problem2.java)

Your solution is excellent! You have implemented an efficient dynamic programming approach that only uses two variables (prev and current) to keep track of the maximum robbings up to the previous two houses. This is optimal in terms of both time and space complexity.

Strengths:

• Correctness: Your solution correctly computes the maximum amount that can be robbed without alerting the police.
• Time Complexity: O(n) is the best possible for this problem.
• Space Complexity: O(1) is optimal since you are using only constant extra space.
• Code Quality: The code is concise, well-structured, and easy to understand. You have handled the base case for arrays of length 1 appropriately.

One minor improvement: You might want to handle the case when the input array is empty (though the constraints say length >= 1, it's good practice to consider edge cases). For example, if nums.length == 0, your code would throw an exception when accessing nums[0]. However, since the constraints state that the length is at least 1, this is not strictly necessary.

Overall, this is a great solution!

VERDICT: PASS