from bisect import bisect_left, bisect_right
import unittest


def find_intersections(horizontal_segments, vertical_segments, epsilon=0.0):
    horizontal_segments.sort(key=lambda h: h[0][1])  # sortiere nach y

    horizontal_ys = []
    horizontal_x_ranges = []
    for (x1, y), (x2, _) in horizontal_segments:
        if x1 > x2:
            x1, x2 = x2, x1
        horizontal_ys.append(y)
        horizontal_x_ranges.append((x1, x2))

    intersections = []

    for (x, y1), (_, y2) in vertical_segments:
        if y1 > y2:
            y1, y2 = y2, y1

        for idx, y in enumerate(horizontal_ys):
            if y1 - epsilon <= y <= y2 + epsilon:
                x_start, x_end = horizontal_x_ranges[idx]
                if x_start - epsilon <= x <= x_end + epsilon:
                    intersections.append((x, y))

    return intersections

class TestStringMethods(unittest.TestCase):

    def test_sweep(self):
        horizontal = [((1, 2), (5, 2)), ((3, 4), (7, 4))]
        vertical = [((4, 1), (4, 5)), ((6, 3), (6, 6))]

        a = find_intersections(horizontal, vertical)
        self.assertEqual( [(4,2),(4,4),(6,4)], a) 

    def test_tol(self):
        horizontal = [((0, 0), (10, 0))]
        vertical = [((4, 0.6), (4, 5)), ((6, 0.2), (6, 6)),((8,-0.2),(8, 4))]

        b = find_intersections(horizontal, vertical, 0.5)
        self.assertEqual( length(b), 2) 


if __name__  == '__main__':
    unittest.main()