bobosivic

static void merge(int arr[], int l, int m, int r, String decision){
        int a = m - l +1;
        int b = r - m;

        int left[] = new int [a];
        int right[] = new int [b];

        for (int i=0;i<a;++i){
            left[i] = arr[l + i];
        }
        for (int j=0;j<b;++j){
            right[j] = arr[m+1 + j];
        }

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

        while( i < a && j < b){
            if (decision.equalsIgnoreCase("A"))
                if(left[i] <= right[j]){ //(<= if ascending)
                    arr[k] = left[i];
                    i++;
                }
                else{
                    arr[k] = right[j];
                    j++;
                }
                k++;
            }
            if (decision.equalsIgnoreCase("D")){
                if(left[i] >= right[j]){ //(>=  if descending)
                    arr[k] = left[i];
                    i++;
                }
                else{
                    arr[k] = right[j];
                    j++;
                }
                k++;
            }
        while(i < a){
            arr[k] = left[i];
            i++; k++;
        }
        while(j < b){
            arr[k] = right[j];
            j++; k++;
        }
    }