SYBCom(CA) DS Practical Slip 13 Q.B

Write a C program to accept and sort n elements in ascending order by using merge sort.

#include <stdio.h>
#include <stdlib.h>

// Function to merge two subarrays
void merge(int arr[], int left, int mid, int right) {
    int n1 = mid - left + 1;
    int n2 = right - mid;

    int L[n1], R[n2];

    for(int i = 0; i < n1; i++)
        L[i] = arr[left + i];
    for(int j = 0; j < n2; j++)
        R[j] = arr[mid + 1 + j];

    int i = 0, j = 0, k = left;

    while(i < n1 && j < n2) {
        if(L[i] <= R[j])
            arr[k++] = L[i++];
        else
            arr[k++] = R[j++];
    }

    while(i < n1)
        arr[k++] = L[i++];
    while(j < n2)
        arr[k++] = R[j++];
}

// Merge Sort function
void mergeSort(int arr[], int left, int right) {
    if(left < right) {
        int mid = left + (right - left) / 2;

        mergeSort(arr, left, mid);
        mergeSort(arr, mid + 1, right);

        merge(arr, left, mid, right);
    }
}

int main() {
    int n;

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

    int arr[n];

    printf("Enter %d elements:\n", n);
    for(int i = 0; i < n; i++)
        scanf("%d", &arr[i]);

    mergeSort(arr, 0, n - 1);

    printf("Sorted array in ascending order:\n");
    for(int i = 0; i < n; i++)
        printf("%d ", arr[i]);
    printf("\n");

    return 0;
}