Find the subtraction of sum of nodes on even level and odd level.

Question

               40

       30              60

   25      35      50      70

 12  27  32

Answer = -59

Answer 1

void sumlevel(node *root, int *esum, int *osum, int h)
{
    if (root == NULL)
        return 0;
    else
    {
        if(h %2 == 0)
            *esum = *esum + root->val;
        else
            *osum = *osum + root->val;
        sumlevel(root->left, esum, osum, h+1);
        sumlevel(root->right, esum, osum, h+1);
    }
}
int diff_of_level(node *root)
{
    int esum = 0, osum = 0;
    int h;
    sumlevel(root, &esum, &osum, 1);
    return esum - osum;
}