Contact Tracing Exposure Count

Problem

Count the distinct nodes exposed to a fixed infected set during a time window.

For snapshots with indices from start_time up to start_time + t - 1, every edge with an infected endpoint exposes the other endpoint. Return the number of exposed nodes that are not themselves infected. snapshots is a list of edge lists.

Hint

Contact tracing looks one snapshot window back from each confirmed case.

Test cases

case 1

in: [4,[[[0,1],[2,3]],[[1,2]],[[0,3]]],[0],0,2]

expected: 1

case 2

in: [4,[[[0,1],[2,3]],[[1,2]],[[0,3]]],[1],0,3]

expected: 2

case 3

in: [4,[[[0,1],[2,3]]],[0],0,1]

expected: 1

case 4

in: [4,[[[0,1]]],[2],0,1]

expected: 0

Starter codePython

def contact_tracing_count(n, snapshots, infected, start_time, t):
    # Your code here
    pass

4 test cases · run your code against them in the editor