void merge_sort(int* arr, int left_b, int right_b) {
    int temp;
    if (left_b < right_b)
        if (right_b - left_b == 1) {
            if (arr[left_b] > arr[right_b]) {
                temp = arr[right_b];
                arr[right_b] = arr[left_b];
                arr[left_b] = temp;
            }

        }
        else {
            merge_sort(arr, left_b, left_b + (right_b - left_b) / 2);
                merge_sort(arr, left_b + (right_b - left_b) / 2 + 1, right_b);
                int* dop = new int[right_b];
            int left_start = left_b;
            int mid = left_b + (right_b - left_b) / 2;
            int right_start = mid + 1;
            int sok = 0;
            while (left_start <= mid && right_start <= right_b) {
                if (arr[left_start] < arr[right_start]) {
                    dop[sok] = arr[left_start];
                    ++left_start;
                }
                else {
                    dop[sok] = arr[right_start];
                    ++right_start;
                }
                ++sok;
            }
            while (left_start <= mid) {
                dop[sok] = arr[left_start];
                ++left_start;
                ++sok;
            }
            while (right_start <= right_b) {
                dop[sok] = arr[right_start];
                ++right_start;
                ++sok;
            }
            for (int k = 0; k < sok; ++k) {
                arr[left_b + k] = dop[k];
            }
        }

}