merge_sort.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 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++];
}
void mergeSort(int arr[], int left, int right){
    if(left < right){
        int mid = (left + right) / 2;
        
        mergeSort(arr, left, mid);
        mergeSort(arr, mid + 1, right);
       
        merge(arr, left, mid, right);
    }
}
int main() {
    int n;
    cin >> n;
    int arr[n];
    for(int i = 0; i<n; i++){
        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;
}