Completed PreCourse-2

[rvuyyuru7]

No description provided.

[super30admin]

Exercise_1.java (Binary Search):

• Correctness: The binary search implementation is mostly correct but has a minor issue in the loop condition (while (l < r)). It should be while (l <= r) to handle cases where the target is at the last remaining element. The student identified their initial mistake with x < mid vs x < arr[mid], which is good.
• Time Complexity: Correctly identified as O(logN).
• Space Complexity: Correctly identified as O(1).
• Code Quality: The code is clean and readable. The comment about the initial mistake is helpful for debugging.
• Efficiency: The loop condition should be fixed for correctness.

Exercise_2.java (QuickSort):

• Correctness: The implementation is correct, including the partition logic and recursive sorting. The student mentioned watching videos to recollect QuickSort, which is a good learning approach.
• Time Complexity: Correctly identified as O(NlogN) on average.
• Space Complexity: Correctly identified as O(logN) due to recursive calls.
• Code Quality: The code is well-structured and readable. The comments are helpful.
• Efficiency: The additional checks (if (pivotIndex - 1 > low) and if (pivotIndex + 1 < high)) are unnecessary since the base condition (low < high) already handles this.

Exercise_3.java (Linked List Middle Element):

• Correctness: The implementation is correct, using fast and slow pointers to find the middle element.
• Time Complexity: Correctly identified as O(N).
• Space Complexity: Correctly identified as O(1).
• Code Quality: The code is clean and follows best practices. The use of fast and slow pointers is well-implemented.
• Efficiency: No optimizations needed.

Exercise_4.java (MergeSort):

• Correctness: The implementation is correct, including the merge logic and recursive sorting. The student mentioned watching videos to recollect MergeSort, which is a good learning approach.
• Time Complexity: Correctly identified as O(NlogN).
• Space Complexity: Correctly identified as O(N) for the temporary arrays.
• Code Quality: The code is well-structured and readable. The comments are helpful.
• Efficiency: No optimizations needed.

Exercise_5.java (Iterative QuickSort):

• Correctness: The implementation is correct, using a stack to simulate recursion. The XOR-based swap is a clever optimization but could be less readable for some.
• Time Complexity: Correctly identified as O(NlogN) on average.
• Space Complexity: Correctly identified as O(1) for the iterative approach.
• Code Quality: The code is well-structured, but the XOR swap might be less intuitive. A traditional swap with a temporary variable might be more readable.
• Efficiency: The XOR swap is efficient but could be replaced with a traditional swap for better readability.

General Feedback:

• The student has a good understanding of the algorithms and their complexities.
• The code quality is high, with clear comments and structure.
• Minor improvements can be made in the binary search loop condition and the QuickSort recursive checks.
• The student's approach to learning (watching videos) is commendable.