void printAllPaths(struct node* root, int *arr, int len)
{
    if(root == NULL)
        return;

    arr[len++] = root->data;

    if((root->left == NULL) && (root->right==NULL))
    {
        int i=0;
        for(i=0; i < len; i++)
            printf("%d ", arr[i]);
        printf("\n");

        return;
    }

    printAllPaths(root->left, arr, len);
    printAllPaths(root->right, arr, len);
}