Complete20_21

[dhruvil15]

No description provided.

[super30admin]

The Coin Change (Problem20.java)

Your solution is correct and efficient. You have implemented the standard dynamic programming approach for the coin change problem using a 1D DP array. Well done!

However, there are a few areas for improvement:

1. Instead of using a magic number like 99999 to represent infinity, it is better to use amount + 1 because the maximum number of coins needed cannot exceed amount (if there is a coin of 1). This makes the code more robust and readable.
2. The variable names `

VERDICT: NEEDS_IMPROVEMENT

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House Robber (Problem21.java)

Your solution is excellent! You have implemented an efficient dynamic programming approach that runs in linear time and constant space. This is the optimal solution for the House Robber problem.

Strengths:

• You correctly handled base cases (n=1 and n=2).
• You used a bottom-up DP approach with state variables prev and curr to avoid using extra arrays.
• The code is concise and easy to understand.

Areas for improvement:

• While your solution is already optimal, you might consider adding a comment to explain the logic briefly, especially for those who might be new to dynamic programming. For example, you could note that prev represents the maximum robbings up to house i-2, and curr represents the maximum up to house i-1.
• Also, consider initializing prev and curr for the case when the array is empty (though constraints say n>=1, it's good practice to handle edge cases explicitly). However, since the constraints ensure n>=1, it's not strictly necessary.

Overall, this is a very strong solution. Keep up the good work!

VERDICT: PASS