ds-lab-codes/MergeSort.c

#include <stdio.h>

// Function to merge two halves
void merge(int a[], int left, int mid, int right) {
    int i = left, j = mid + 1, k = 0;
    int temp[right - left + 1];

    // Merge elements into temp[]
    while (i <= mid && j <= right) {
        if (a[i] <= a[j])
            temp[k++] = a[i++];
        else
            temp[k++] = a[j++];
    }

    // Copy remaining elements from left half
    while (i <= mid)
        temp[k++] = a[i++];

    // Copy remaining elements from right half
    while (j <= right)
        temp[k++] = a[j++];

    // Copy temp[] back to original array
    for (i = left, k = 0; i <= right; i++, k++)
        a[i] = temp[k];
}

// Recursive merge sort
void mergeSort(int a[], int left, int right) {
    if (left < right) {
        int mid = (left + right) / 2;

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

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

int main() {
    int n, i;

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

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

    mergeSort(a, 0, n - 1);

    printf("Sorted list (Ascending Order):\n");
    for (i = 0; i < n; i++)
        printf("%d ", a[i]);

    printf("\n");
    return 0;
}