Kth Smallest and Largest Elements in C

Summary: This C program finds the Kth smallest and Kth largest elements from an array by sorting the array in ascending order using Bubble Sort. It then prints these values along with appropriate ordinal suffixes.

#include <stdio.h>

// Function to perform bubble sort
void bubbleSort(int arr[], int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (arr[j] > arr[j + 1]) {
                // Swap elements
                int temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n, k;

    // Get the number of elements
    printf("Enter the number of elements: ");
    scanf("%d", &n);

    // Check constraints
    if (n < 1 || n > 1000) {
        printf("Invalid number of elements! Please enter a value between 1 and 1000.\n");
        return 1;
    }

    int arr[n];

    // Get the array elements
    printf("Enter the elements: ");
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    // Get the value of k
    printf("Enter the value of k: ");
    scanf("%d", &k);

    // Check constraints for k
    if (k < 1 || k > n) {
        printf("Invalid value of k! Please enter a value between 1 and %d.\n", n);
        return 1;
    }

    // Sort the array in ascending order using bubble sort
    bubbleSort(arr, n);

    // Find the Kth smallest and Kth largest elements
    int kth_smallest = arr[k - 1];   // Kth smallest element is at index k-1
    int kth_largest = arr[n - k];    // Kth largest element is at index n-k

    // Print the results
    printf("%d", k);
    // Handling ordinal suffixes for English (1st, 2nd, 3rd, 4th, etc.)
    if (k % 10 == 1 && k % 100 != 11) {
        printf("st");
    } else if (k % 10 == 2 && k % 100 != 12) {
        printf("nd");
    } else if (k % 10 == 3 && k % 100 != 13) {
        printf("rd");
    } else {
        printf("th");
    }
    printf(" smallest element: %d\n", kth_smallest);

    printf("%d", k);
    if (k % 10 == 1 && k % 100 != 11) {
        printf("st");
    } else if (k % 10 == 2 && k % 100 != 12) {
        printf("nd");
    } else if (k % 10 == 3 && k % 100 != 13) {
        printf("rd");
    } else {
        printf("th");
    }
    printf(" largest element: %d\n", kth_largest);

    return 0;
}

Explanation:

Program Overview:

This program finds the Kth smallest and Kth largest elements from an array by sorting the array in ascending order using Bubble Sort. It also displays the results with appropriate ordinal suffixes.

Function - bubbleSort():

The bubbleSort() function sorts the array by comparing adjacent elements and swapping them if they are in the wrong order. This process is repeated until the array is sorted.

Main Function Workflow:

1. Input Array Size:
   • The user enters the size of the array n.
   • Constraints ensure that n is between 1 and 1000.
2. Input Array Elements:
   • The user inputs n elements of the array.
3. Input Value of k:
   • The value of k is input by the user.
   • A validation check ensures that k is between 1 and n.
4. Sort the Array:
   • bubbleSort() is used to sort the array in ascending order.
5. Find Kth Smallest and Kth Largest Elements:
   • The Kth smallest element is at index k - 1.
   • The Kth largest element is at index n - k.
6. Print the Results:
   • The results are printed with appropriate ordinal suffixes (e.g., 1st, 2nd, 3rd, 4th).

Edge Cases and Error Handling:

• Invalid Array Size: An error message is shown if the size is less than 1 or greater than 1000.
• Invalid Value of k: An error message is shown if k is outside the valid range.

Time Complexity:

• O(n^2) due to the nested loops used in bubble sort.

Space Complexity:

• O(1) as the operations are performed in-place with minimal extra space.