Twopointers 2

[MeghaN28]

No description provided.

[super30admin]

Merging of 2 arrays (MergeSorted.java)

The solution is correct and efficient. It follows the standard approach for merging two sorted arrays in-place. The code is clean and well-commented. However, there is one minor issue: the code does not handle the case when nums1 has remaining elements? Actually, it does not need to because the remaining elements in nums1 are already in the correct position. So the code is correct.

But note: the student's code does not have a loop to copy remaining elements from nums1. This is intentional because those elements are already in place. Only the remaining elements from nums2 need to be copied. So the code is correct.

One improvement could be to use more descriptive variable names, such as p1, p2, and idx to match common conventions for this problem. However, i, j, and k are also acceptable and widely used.

Overall, the solution is excellent.

VERDICT: PASS

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Search 2D sorted matrix II (RemoveDuplicates.java)

Note: The student's solution is for a different problem (RemoveDuplicates) than the one we are evaluating (Search 2D sorted matrix II). This might be a mistake. Let me check the problem again.

Wait, the student provided a solution for "RemoveDuplicates" but the problem we are evaluating is "Search 2D sorted matrix II". This is a mismatch.

Given that, the student's solution does not address the problem at all. Therefore, it cannot be correct.

Let me proceed with the evaluation accordingly.

VERDICT: NEEDS_IMPROVEMENT

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Edit and Remove Duplicates in an array (Searchinmatrix.java)

It seems there has been a mix-up in the problem you solved. The problem you addressed is "Search in a Matrix" (likely LeetCode problem 240), but the assigned problem is "Remove Duplicates from Sorted Array II" (LeetCode problem 80).

For the "Search in a Matrix" problem, your solution is excellent. You have correctly implemented the algorithm starting from the top-right corner, which efficiently reduces the search space by moving left or down based on the comparison with the target. Your time and space complexity analyses are accurate, and the code is clear and concise.

However, for the assigned problem, you need to implement a solution that removes duplicates from a sorted array in-place, allowing each element to appear at most twice. You should focus on solving the correct problem.

For the "Remove Duplicates from Sorted Array II" problem, you can use a two-pointer approach similar to the reference solution. The idea is to traverse the array with a fast pointer and use a slow pointer to build the new array. You need to keep track of the count of consecutive duplicates and only allow up to two occurrences.

Here is a suggested approach for the correct problem:

• Initialize two pointers: slow (to place the next valid element) and fast (to traverse the array).
• Use a variable to count consecutive occurrences of the same element.
• For each element, if it is the same as the previous, increment the count; otherwise, reset the count to 1.
• If the count is <= 2, copy the element to the slow pointer and increment slow.
• Increment fast until the end of the array.
• Return slow, which will be the new length.

VERDICT: NEEDS_IMPROVEMENT