[
    [1, 2, 3, 4, 5],
    [1, 2, 3, 4, 5],
    [1, 2, 3, 4, 5, 6],
    [6, 7, 8],
    [8, 9, 10, 11]
 ]

How to determine that the elements of the outer array are equal or have intersections, how to do it with the lowest time complexity?