Merge Without Extra Space 0.23 s

//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;


// } Driver Code Ends
class Solution{
    public:
        //Function to merge the arrays.
        void merge(long long arr1[], long long arr2[], int n, int m)
        {
            // code here
            int l=n-1;
            int r=0;
            while(l>=0 && r<m)
            {
                if(arr1[l]>arr2[r])
                {
                    int t=arr1[l];
                    arr1[l]=arr2[r];
                    arr2[r]=t;
                    l--;
                    r++;
                }
                else
                {
                    break;
                }
            }
            sort(arr1,arr1+n);
            sort(arr2,arr2+m);
        }
};

//{ Driver Code Starts.

int main()
{

    int T;
    cin >> T;

    while(T--){
        int n, m;
        cin >> n >> m;

        long long arr1[n], arr2[m];

        for(int i = 0;i<n;i++){
            cin >> arr1[i];
        }

        for(int i = 0;i<m;i++){
            cin >> arr2[i];
        }
        Solution ob;
        ob.merge(arr1, arr2, n, m);

        for (int i = 0; i < n; i++)
            cout<<arr1[i]<<" ";


        for (int i = 0; i < m; i++)
            cout<<arr2[i]<<" ";

        cout<<endl;
    }

    return 0;
}

// } Driver Code Ends