def compute_similarity_weight(num_contacts: int, max_val: float=2.0, k: float=1.0) -> float:
"""
Compute the similarity weighting factor based on the number of user-item interactions.
Args:
num_contacts (int): Number of user-item interactions.
max_val (float): Maximum value for the similarity weighting factor.
k (float): Scaling factor that controls the rate of increase of the similarity weighting factor.
Returns:
float: Similarity weighting factor between 0 and 2.
The factor approaches 2 as the number of contacts increases.
0 if there are no contacts, 1 if there is one contact, and close to 2 if there are many contacts by default.
"""
return max_val * num_contacts / (num_contacts + k)
