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Question 1: Determine what the following recursive "mystery" function computes when given a pointer to the root node of a binary tree.
struct bt_s { int key; struct bt_s *left, *right; } bt_t;
int MFunc (bt_t *T) {
int N1, N2;
if (T == NULL) return -1;
N1 = MFunc(T->left);
N2 = MFunc(T->right);
return (N1 > N2 N1 : N2) + 1;
}