I have two sets of tokenised sentences A and B and I want to calculate the overlap between them in terms of common tokens. For example, the overlap between two individual sentences a1 today is a good day and b1 today I went to a park is 2 (today and a). I need a simple string matching method, without fuzzy or advanced methods. So the result is a matrix between all sentences in A and B with an overlap count for each pair.
The problem is that, while trivial, it is a quadratic operation (size of A x size of B pair-wise comparisons). With large data, the computation gets very slow very quickly. What would be a smart way of computing this avoiding pair-wise comparisons or doing them very fast? Are there packages/data structures particularly good for this?