@testset "1552.magnetic-force-between-two-balls.jl" begin
    @test max_distance([1,2,3,4,7], 3) == 3
    @test max_distance([5,4,3,2,1,1000000000], 2) == 999999999
    @test max_distance([153, 66, 174, 97, 76, 101, 189, 47, 94, 141, 30, 135, 112, 15, 59, 134, 52, 108, 10, 31, 166, 160, 99, 146, 28, 58, 100, 18, 109, 9, 11, 54, 132, 113, 80, 88, 90, 46, 7, 145, 56, 33, 6, 79, 82, 157, 67, 199, 25, 2, 4, 178, 23, 57, 32, 151, 156, 73, 142, 116, 187, 77, 163, 38, 179, 154, 26, 122, 62, 136, 186, 87, 162, 159, 98, 117, 42, 161, 14], 15) == 12
    @test max_distance([153, 66, 174, 97, 76, 101, 189, 47, 94, 141, 30, 135, 112, 15, 59, 134, 52, 108, 10, 31, 166, 160, 99, 146, 28, 58, 100, 18, 109, 9, 11, 54, 132, 113, 80, 88, 90, 46, 7, 145, 56, 33, 6, 79, 82, 157, 67, 199, 25, 2, 4, 178, 23, 57, 32, 151, 156, 73, 142, 116, 187, 77, 163, 38, 179, 154, 26, 122, 62, 136, 186, 87, 162, 159, 98, 117, 42, 161, 14], 20) == 8
end