Merge Sort.cpp

#include <iostream>

using namespace std;
void merge(int arr[],int l, int mid , int r){
      int n1 = mid-l+1;
      int n2 = r-mid;
     
      int a[n1];
      int b[n2];
   
   
     for(int i=0 ; i<n1 ;i++){
            a[i] = arr[l + i];
           
        }
        for(int i=0 ; i<n2 ;i++){
            b[i] = arr[mid + 1 + i];
        }  
            int i =0;
            int j=0;
            int k=l;
           
            while(i<n1 && j<n2){
                if(a[i]<b[j]){
                    arr[k]=arr[i];
                    k++;
                    i++;
                }
            else{
                arr[k] = b[j];
                k++;
                j++;
            }
        }
        while(i<n1){
            arr[k] =a[i];
            k++;
            i++;
        }  
        while(i<n2){
            arr[k] =a[j];
            k++;
            j++;
    }

}




void mergeSort(int arr[] , int l , int r){
   
   
    if(l<r){
        int mid = (l+r)/2;
        mergeSort(arr,l,mid);
        mergeSort(arr,mid+1,r);
       
        merge(arr,l,mid,r);
    }
   
}    
       

int main()
{
    int arr[]={5,4,6,3,2};
    mergeSort(arr,0,4);
    for(int i=0;i<5;i++){
        cout<<arr[i]<<" ";
    }
    cout<<endl;
 return 0;
}