Jaccard Similarity

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Easy

Jaccard similarity measures the overlap between two collections after duplicates are removed. Form sets A and B from the input lists, then compute

J(A, B) = \frac{|A \cap B|}{|A \cup B|}

Here, the numerator counts items shared by both sets, while the denominator counts distinct items present in either set. If both sets are empty, return 0.0. Otherwise return the similarity as a float.

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Examples

Input: set_a = [1, 2, 3], set_b = [2, 3, 4]

Output: 0.500000

Explanation: The intersection has two items and the union has four, giving 2 / 4 = 0.5.

Input: set_a = [1, 2], set_b = [3, 4]

Output: 0.000000

Hint 1

Convert both lists to sets before measuring overlap.

Hint 2

Handle an empty union before performing the division.

Requirements

Treat duplicate input items as a single item.
Divide the intersection size by the union size.
Return 0.0 when both sets are empty.
Return a float from 0.0 through 1.0.

Constraints

set_a and set_b are lists of integers.
Either input list may be empty.
Time limit: 300 ms.

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