Data Structures (BCA) 3rd Sem Previous Year Solved Question Paper 2022

Selection sort is a simple comparison-based sorting algorithm that works by repeatedly selecting the minimum (or maximum) element from the unsorted part of the array and moving it to the sorted part. Here's the algorithm for selection sort:

Algorithm for Selection Sort:
    1. Start with the first element as the minimum (assuming it's the minimum for now).
    2. Compare the minimum with the next element in the unsorted part of the array.
    3. If a smaller element is found, update the minimum to be that element.
    4. Repeat steps 2 and 3 for the entire unsorted part, finding the minimum element in the unsorted portion.
    5. Swap the minimum element with the leftmost element in the unsorted part of the array.
    6. Expand the sorted part to include the newly sorted element.
    7. Repeat these steps for the remaining unsorted part of the array until the entire array is sorted.

Example of Selection Sort:
Let's use an example to illustrate how selection sort works. We want to sort an array of integers in ascending order:
Unsorted Array: [64, 25, 12, 22, 11]
    1. Start with the first element (64) as the assumed minimum.
    2. Compare 64 with the next element (25). Since 25 is smaller, update the minimum to 25.
    3. Continue comparing the minimum (25) with the next element (12) and update the minimum to 12.
    4. Repeat this process for the entire unsorted part of the array. The minimum element in the unsorted part is now 12.
    5. Swap the minimum element (12) with the leftmost element in the unsorted part (64).
        ◦ Unsorted Array: [64, 25, 25, 22, 11]
        ◦ Sorted Array: [12]
    6. Expand the sorted part to include the newly sorted element (12).
        ◦ Unsorted Array: [64, 25, 22, 11]
        ◦ Sorted Array: [12]
    7. Repeat the same process for the remaining unsorted part:
        ◦ Find the minimum (11) and swap it with the leftmost unsorted element (64).
        ◦ Expand the sorted part: [11, 12]
        ◦ Continue until the entire array is sorted.

The sorted array is now complete: [11, 12, 22, 25, 64].

Selection sort is not the most efficient sorting algorithm for large datasets because its time complexity is O(n^2), where 'n' is the number of elements. However, it is easy to understand and implement and can be useful for small datasets or as a building block in more complex sorting algorithms.