Compelted Two-Pointers-2

[irrawaddy28]

No description provided.

[super30admin]

Merge Sorted Array (merge_sorted_array.py)

Excellent work! Your solution demonstrates a strong understanding of the three-pointer technique for in-place merging. Here are some observations:

Strengths:

1. Thorough documentation: Your docstring is exceptional - it explains the problem, both approaches (brute force and optimal), time/space complexity, and even includes a discussion about why we can't start from the beginning of the arrays.
2. Correct implementation: The three-pointer logic is correctly implemented with proper handling of edge cases.
3. Input validation: The assertions at the beginning help catch invalid inputs early.
4. Test coverage: Your test cases cover the main examples from the problem.
5. Optimal complexity: Your solution achieves O(M+N) time and O(1) space, matching the reference.

Minor suggestions:

1. Naming convention: Consider using the standard parameter names from the problem (nums1, nums2, m, n) for consistency with the LeetCode problem signature, especially if this is for interview preparation.
2. Return value: The reference solution doesn't return anything (modifies in-place). Your function returns M when N == 0, which is a bit unusual. Consider just returning None for consistency with the problem's expected behavior.
3. Edge case handling: Your if N == 0: return M early return is a nice optimization, but note that the main while loop would also handle this correctly (it would just not execute and the second while loop wouldn't execute either since b would be -1).

Overall, this is a high-quality solution that demonstrates both technical competence and good engineering practices.

VERDICT: PASS

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Search a 2D Matrix II (search_2d_matrix_2.py)

Excellent work! Your solution demonstrates a deep understanding of the problem. Here are some highlights and minor suggestions:

Strengths:

1. Optimal Algorithm Choice: You chose the two-pointer approach which achieves O(m+n) time complexity, beating the reference solution's O(m log n).
2. Excellent Documentation: Your comments thoroughly explain multiple approaches, including why certain starting points (top-left, bottom-right) don't work. This shows strong analytical thinking.
3. Comprehensive Testing: Your test cases cover edge cases like single rows, single columns, and single elements.
4. Multiple Implementations: Providing both top-right and bottom-left starting points demonstrates thoroughness.
5. Clean Code Structure: Functions are well-named and the code is readable.

Minor Suggestions:

1. The empty matrix check if M == 0 could also check if not mat for more Pythonic style.
2. Consider adding a docstring to the test function explaining what each test case validates.
3. The variable names M and N are fine, but lowercase m and n would be more conventional in Python (PEP 8).

Overall, this is an exemplary solution that goes above and beyond the requirements.

VERDICT: PASS

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Remove Duplicates from Sorted Array II (remove_duplicates_from_sorted_array_2.py)

Great work overall! Your solution correctly solves the problem with O(n) time and O(1) space complexity, matching the reference solution. Here are some suggestions:

1. Generalization is a strength: Parameterizing with K is a nice touch that makes your solution more flexible than the reference.

2. Test coverage is excellent: Your test suite covers many edge cases including single elements, all duplicates, mixed cases, and different values of K.

3. Unused import: Remove import copy as it's not used anywhere in your code.

4. Edge case handling: The return -1 for empty array is inconsistent. Since the constraints guarantee nums.length >= 1, you could simplify the edge case handling. Also, returning 1 for a single-element array is correct, but the logic flow could be cleaner.

5. Function naming: Consider more descriptive names like remove_duplicates_two_pointer and remove_duplicates_group_processing instead of numbered suffixes.

6. Code structure: For a LeetCode-style submission, you'd typically need a Solution class with a removeDuplicates method. Your current structure works for standalone testing but may not match the expected interface.

7. Minor optimization in function 2: The inner while loop in remove_duplicates_from_sorted2 could be simplified using slicing or direct assignment for cleaner code.

VERDICT: PASS