void insertionSort(int arr[], int n) {

    int i, key, j;

    for (i = 1; i < n; i++) {

        key = arr[i];

        j = i - 1;

        while (j >= 0 && arr[j] > key) {

            arr[j + 1] = arr[j];

            j = j - 1;

        }

        arr[j + 1] = key;

    }

}