mergeSort.cpp

#include <iostream>
using namespace std;

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

    int leftArr[n1], rightArr[n2];

    for (int i = 0; i < n1; i++)
        leftArr[i] = arr[left + i];
    for (int i = 0; i < n2; i++)
        rightArr[i] = arr[mid + 1 + i];

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

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

    while (i < n1) {
        arr[k++] = leftArr[i++];
    }

    while (j < n2) {
        arr[k++] = rightArr[j++];
    }
}

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 arr[10];
    int n;
    cout<<"Enter the array size <=10:";
    cin >> n;
    if (n > 10 || n <= 0) {
        cout << "Invalid size. Please enter a size between 1 and 10." << endl;
        return 1;
    }
    cout << "Enter the array elements: ";
    for (int i = 0; i < n; i++) {
        cout << "-> ";
        cin >> arr[i];
    }

    mergeSort(arr, 0, n - 1);

    cout << "Sorted array: ";
    for (int i = 0; i < n; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;

    return 0;
}