Complete Precourse-2

[paridhimalviya]

Exercise_1 : Binary Search.

Exercise_2 : Quick sort.

Exercise_3 : Find Mid Point of a Singly Linked List.

Exercise_4 : Merge Sort.

Exercise_5 : Iterative Quick Sort.

[super30admin]

The student's solution demonstrates a good understanding of various algorithms and data structures, including binary search, merge sort, quick sort (both recursive and iterative versions), linked lists, and stacks. Here are some specific observations:

Strengths:

1. The binary search implementation is correct and includes both iterative and recursive approaches.
2. The merge sort implementation correctly follows the divide-and-conquer strategy.
3. The quick sort implementations (both recursive and iterative) are correctly implemented with proper partitioning logic.
4. The linked list and stack implementations are well-structured and demonstrate good understanding of these data structures.
5. Code is generally well-commented and organized.

Areas for Improvement:

1. In the binary search implementation, the recursive version returns nil when the target is not found, while the iterative version returns -1. This inconsistency should be fixed to maintain uniformity.
2. The partitionTheArrayBasedOnAPivot function in IterativeQuickSort.swift could be renamed to something more concise like partition.
3. The mergeTwoSortedArray and mergeTwoSortedArrays functions in MergeSort.swift are duplicates with slightly different implementations. One should be removed to avoid redundancy.
4. Some functions could benefit from more descriptive parameter names (e.g., a and b in merge functions could be firstArray and secondArray).
5. The date in the file headers (12/17/25 etc.) appears to be incorrect or placeholder values.
6. The QuickSort class doesn't print the sorted array in the initializer, unlike other sorting implementations.

General Suggestions:

1. Consider adding more test cases, especially edge cases (empty arrays, arrays with duplicate values, etc.).
2. For the linked list implementations, consider adding more functionality like node removal by value or index.
3. The stack implementation could benefit from a count property to match common stack interfaces.

[super30admin]

The student's solution demonstrates a good understanding of various algorithms and data structures. Here's a detailed evaluation:

Strengths:

1. BinarySearch implementation is correct with both iterative and recursive approaches.
2. MergeSort is correctly implemented with proper merging of sorted arrays.
3. QuickSort implementations (both recursive and iterative) are correct with proper partitioning.
4. LinkedList and Stack implementations are well-structured.
5. Code is generally readable with good use of comments and descriptive variable names.

Areas for Improvement:

1. BinarySearch's recursive implementation returns nil in some cases but -1 in others - should be consistent (preferably nil for not found).
2. In MergeSort, there's a duplicate method mergeTwoSortedArrays that isn't used - should be removed.
3. QuickSort's partition function could be made more generic to handle different types.
4. Some methods like swap in QuickSort could be replaced with Swift's built-in swapAt.
5. The Stack implementation could benefit from protocol conformance (like Swift's Collection protocol).
6. Edge cases could be better handled in some places (like empty arrays in sorting algorithms).
7. Some class names could be more descriptive (e.g., "Untitled.swift" should be renamed).

Time Complexity:

1. BinarySearch: O(log n) for both implementations - correct.
2. MergeSort: O(n log n) - correct.
3. QuickSort: O(n log n) average case, O(n²) worst case - correct.
4. Stack operations: O(1) - correct.

Space Complexity:

1. BinarySearch: O(1) for iterative, O(log n) for recursive - correct.
2. MergeSort: O(n) - correct.
3. QuickSort: O(log n) for recursive (call stack), O(n) for iterative (explicit stack) - correct.
4. Stack: O(n) - correct.